Architectural Prototyping as Research-by-Design: Producing Situated Knowledge Through Temporary Public Interventions

Architectural Prototyping as Research-by-Design: Producing Situated Knowledge Through Temporary Public Interventions | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Architectural Prototyping as Research-by-Design: Producing Situated Knowledge Through Temporary Public Interventions Francesco Rossini, Filipe Afonso This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9461708/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This paper investigates how full-scale architectural prototyping can function as a research-by-design method for generating integrated knowledge through implementation in real urban conditions. The argument is developed through the Ladder Street Cultural Space (LSCS), a temporary project realised for five weeks in an underutilised sitting-out area in one of Hong Kong's oldest districts. Fabricated in Expanded Polystyrene (EPS) panels through parametric computational design methods, the project integrated a community library, an exhibition space, and a seating area. LSCS is part of a broader research investigation on how to reactivate underutilised open spaces in high-density cities. The article argues that an architectural prototype situated within the public realm constitutes a research device that activates regulatory, social, and material conditions, generating knowledge that other research methods cannot easily produce. Extending existing frameworks for research-by-design, it treats the public space context as a constitutive dimension of the research rather than a neutral backdrop. Findings demonstrate that LSCS revealed how a specific geometric configuration organises collective occupation, activating new patterns of social use and community engagement, and how public space governance frameworks in Hong Kong shape the spatial conditions and implementation, while also confirming the active role of materiality and fabrication processes in shaping design decisions. Although site-specific, these findings ground a methodological framework transferable to other urban contexts. The paper advances a methodological agenda for practice-based architectural research in urban contexts, in which temporality is not a limitation but a productive condition of inquiry. Architecture Prototypes Research-by-Design Temporary Urban Interventions Robotic Fabrication Public Space Activationù Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 1. Introduction In Invisible Cities , Italo Calvino ( 2006 ) describes Sophronia as a city composed of two halves: one built of stone, marble and concrete; the other an amusement park of rides and entertainments. In the narrative, Calvino inverts the apparent logic of permanence: the stone city is periodically dismantled and moved, while the funfair remains. This incipit raises a question that frames the inquiry of this paper: how should we interpret permanence and temporality in the study of cities? The question opens a broader argument about temporality in architecture: not as a limiting condition, but as a productive one through which urban knowledge can be generated. The paper addresses the following research question: how can full-scale architectural prototyping function as a research-by-design method capable of generating material, spatial, social and institutional knowledge in an integrated manner? We argue that a prototype situated within the public realm is not simply a technical artefact to be evaluated for performance, but a research device that activates real conditions (regulatory, social and material) that remain inaccessible through simulation or conventional design development alone. This position extends existing frameworks for research-by-design (Schön, 1983 ; Cross, 2007 ) by treating the public space context as a constitutive dimension of the research rather than a neutral backdrop. The Ladder Street Cultural Space (LSCS) provides the empirical ground for this investigation: a temporary architectural installation developed for an underutilised sitting-out area in the Sheung Wan district of Hong Kong. Realised through a parametric computational workflow and robotic hot-wire cutting of Expanded Polystyrene (EPS) panels, the project operated at full scale for five weeks, integrating a community library, exhibition space and seating area. The choice of EPS was motivated by its suitability for robotic fabrication, its structural behaviour at architectural scale and the opportunity it offered to examine material performance, logistics and end-of-life management within a single experimental cycle. The paper articulates and empirically grounds a framework for understanding architectural prototyping in public space as an epistemic instrument, capable of generating knowledge across technical, spatial, social, and institutional domains in an integrated manner. This framework is developed through the LSCS project, which demonstrates how a full-scale temporary intervention in an underutilised urban space can simultaneously function as a fabrication research platform, a catalyst for social activation, and a means of revealing governance conditions that other research methods cannot easily access. The following sections present the theoretical context, the making process, and the findings of the LSCS, concluding with reflections on the implications of this approach for practice-based architectural research. 2. Research Context 2.1. Temporality and Architectural Experimentation in Public Space Temporary architectural interventions provide a productive framework through which temporality can be explored as a design condition, translating time-limited processes into spatial, material and social configurations. Within rapidly evolving urban contexts, temporary urbanism has increasingly functioned as a flexible instrument for testing spatial strategies that permanent construction cannot accommodate. As Bishop and Williams ( 2012 ) argue, temporary activities reflect a bottom-up current within contemporary society, through which people reappropriate urban space to suit emerging needs and lifestyles. Historically, ephemeral architecture has played a central role in shaping civic life, from Renaissance ceremonial arches and stage sets that translated collective rituals into spatial form (Gritti, 2024 ), to contemporary installations at events such as the Salone del Mobile or the Venice Architecture Biennale, contexts that offer opportunities to test unconventional materials, fabrication methods and spatial configurations under real conditions. The temporary nature of these interventions, structures that can be built and dismantled within a limited period of time, gives them the potential to attract broad public attention and media interest. In many cases they can be realised directly by the architects themselves, offering opportunities to explore construction methods and budgetary requirements as a way of searching for the new in both architectural practice and discourse (Tuncbilek, 2020 ). Their limited duration enables experimentation, responsiveness and adaptation to shifting urban circumstances (Coar, 2011 ). These interventions transform existing urban spaces into temporary laboratories, reframing how people perceive and inhabit the city. As Cattiodoro ( 2012 ) notes, the creative and technical expertise required to design temporary structures is as rigorous as that demanded by permanent architecture, with design processes frequently involving unconventional materials and fabrication methods that challenge established spatial conventions. Yet much of the discourse surrounding temporary architecture has emphasised symbolic, event-based or programmatic dimensions, inviting reflection on collective spatial practices (McGillivray et al., 2025 ), while less attention has been devoted to understanding how full-scale temporary interventions operate as research instruments embedded in governance frameworks, material constraints and fabrication processes. Within this expanded understanding, temporary architectural interventions can be reconsidered as epistemic devices, contexts in which design decisions, institutional regulation and material performance converge and mutually condition one another. This reframing positions architectural prototyping in public space not merely as spatial activation, but as a research-by-design practice grounded in the contingencies of real urban settings. 2.2. Research-by-Design and Prototyping as Knowledge Production Research-by-design emerges from a broader reconceptualisation of design as a discipline of inquiry that extends beyond its practical dimension (Fraser, 2013 ). According to Schön ( 1983 ), professional knowledge is not applied from theory to practice but generated within practice itself through cycles of action and reflection, a process he described as reflection-in-action . This reframes design from a technical discipline to an epistemic one, in which knowledge is produced through making. Building on this, Cross ( 2007 ) identified design as a specific way of knowing, distinct from scientific or humanistic inquiry. In this sense, architects and designers use drawings, models and prototypes as instruments through which ideas are developed, tested and revised. This explorative and iterative form of work generates new understanding by bringing concepts into physical form. According to Frayling ( 1993 ), design research can be understood as research into , research through , or research for art and design, each implying a different relationship between practice and knowledge production. Research through design uses practice as a means of inquiry but requires explicit documentation of the process; research for design is that in which thinking is embodied in the artefact itself, communicable through visual or material form. Full-scale architectural prototyping as tested in LSCS operates across both categories: the artefact itself constitutes a primary element of knowledge production, while the documentation of the fabrication process, spatial observations and institutional negotiations makes that knowledge communicable beyond the work itself. Prototypes, as argued by Lim et al. ( 2008 ), are instruments for exploring a design concept: they isolate specific qualities, give them physical form, and enable reflection that abstract thinking alone cannot support, while also testing decisions shaped by external constraints, whether material, spatial, or regulatory. As Kannabiran and Bødker ( 2020 ) observe, different prototyping techniques enable different modes of inquiry, with varied intentions and outcomes. This body of work has considerably advanced understanding of prototyping as an epistemic practice within design research, and recent scholarship continues to expand its scope across disciplinary contexts (Ferraris & Nimkulrat, 2025 ). However, the majority of these frameworks have been developed in relation to controlled studio environments, scaled models, and digital or product design contexts. Full-scale architectural prototypes deployed in real public space for extended periods, structured as deliberate research instruments rather than event-driven pop-up interventions, remain comparatively rare in the literature. This relative lack of examples reflects institutional conditions such as limited research funding and persistent scepticism toward practice-based inquiry in architectural academia, rooted in part in what Jonas ( 2007 ) describes as the still weak epistemological status of research-through-design as a mode of knowledge production. It also raises methodological concerns about the difficulty of making the designer's decision-making process sufficiently transparent, given that design research requires explicit documentation and communication of results in re-usable form (Cross, 2007 ), and the inherent ambiguity between professional practice and research activity (Biggs & Büchler, 2008 ). To these established limitations, architectural prototyping implemented in a real urban context adds a further layer of operational complexity that studio-based research does not encounter: negotiating safety requirements, institutional permissions, and civic responsibilities introduces constraints that directly shape the research process and outcomes (Liotta & Louyot, 2022 ). This approach resonates with what Rogers ( 2011 ) describes as prototyping in the wild, evaluating design interventions in situ rather than in controlled settings, here transposed from interaction design to the context of full-scale architectural research. Design decisions emerge from and respond to particular socio-spatial and regulatory conditions, producing knowledge that is situated rather than generic. This site-specificity is not a methodological limitation but an epistemically productive condition: a prototype embedded in a real urban context generates knowledge about material performance, spatial occupation, and institutional governance that controlled research settings cannot access. 2.3. Digital Fabrication and Material Performance in Architectural Research In recent decades, computational design and robotic fabrication have emerged as key drivers of innovation in architectural production, enabling the generation of complex geometries and more adaptive design processes (Caetano et al., 2019 ). Within experimental and temporary architecture, these tools have evolved into accessible platforms that support architects in managing increasing levels of complexity, establishing a direct link between design generation and fabrication logic (Braumann & Brell-Cokcan, 2011 ). Parametric modelling has expanded traditional design approaches by enabling real-time manipulation of geometric parameters, rapid exploration of design variations, and iterative refinement, conditions that are particularly productive in research contexts where the design-to-fabrication process is itself an object of inquiry (Naboni et al., 2019 ). The field of robotic fabrication has advanced considerably with the emergence of parametric robot-control software that integrates design generation and fabrication logic within unified workflows, streamlining the translation from digital models to physical production. Among these tools, KUKA|PRC, a plugin developed for visual programming environments, exemplifies this shift by directly linking computational modelling with robotic execution, and was adopted as the primary design-to-fabrication platform for the LSCS project. Within such workflows, material properties directly condition the fabrication process: as Menges and Reichert ( 2015 ) argue, materials embed characteristics that condition fabrication strategies, geometric possibilities, and spatial outcomes, becoming active parameters in the design process. In research-by-design practice, the constraints introduced by materials within a computational workflow become an opportunity to generate empirical knowledge that extends beyond what simulation alone can achieve. Expanded Polystyrene (EPS) exemplifies this dynamic. Characterised by a lightweight yet rigid structure composed of approximately 98% air, EPS offers high impact resistance, structural stability, and precise shapeability through robotic hot-wire cutting, which enables the fabrication of complex three-dimensional geometries at architectural scale (Park et al., 2022 ; Sulong et al., 2019 ). Its sensitivity to temperature, cutting speed, and wire tension means that material behaviour and computational precision interact continuously throughout fabrication, requiring calibration and generating knowledge that cannot be fully anticipated at the modelling stage. Precedents such as Kwangho Lee's EPS Grotto (2014) and Plasticity Pavilion by Justin Diles demonstrate how EPS can serve as a medium for investigating tectonic, structural, and experiential dimensions of architectural form beyond its conventional applications (Diles, 2018 ), an approach that directly informed the development of LSCS. Despite its advantages for experimental fabrication, EPS raises environmental concerns related to plastic waste; when properly managed and recycled, however, its impact can be substantially reduced (Lim et al., 2021 ). In the LSCS project, the integration of parametric modelling and robotic hot-wire cutting created a direct link between the design process, geometric definition, and material behaviour. Rather than simply automating production, this configuration made the design-to-fabrication process a research instrument through which knowledge about EPS performance, fabrication tolerances, and spatial outcomes was generated progressively during making. 3. Making process 3.1 Design Approach and Prototyping Strategy The LSCS project was developed for a small sitting-out area in the Sheung Wan district of Hong Kong, a neighbourhood characterised by antique shops, art galleries, and a mixed demographic of residents and tourists. The site was underutilised and not integrated into the pedestrian flows and surrounding urban fabric. The intervention aimed to increase its visibility and activate collective use through a distinctive architectural presence capable of drawing attention from adjacent streets. The programme integrated three functions: a community library, an exhibition space, and a seating area. Rather than treating these as separate zones, the design sought spatial continuity between them, supporting multiple forms of use and collective engagement. The spatial organisation of the programme took into account a range of site-specific factors, including topography, pedestrian flows, and the presence of an existing canopy, which informed the positioning of the library within the sheltered area of the space (Fig. 1). The geometry was derived from a series of interlocking circles, producing curvilinear forms that generate smooth transitions between functional areas and a more dynamic spatial experience (Fig. 2). This configuration was also expected to introduce structural advantages over planar vertical surfaces: load distribution along continuous paths improves resistance to wind pressure and dynamic interaction forces (Fig. 3). The design process was structured as a progressive prototyping sequence operating across four scales. Initial 1:50 models evaluated the overall spatial configuration and the relationship between the installation and its urban context. A 1:5 three-dimensional printed model investigated the complex geometries of the installation, including those requireed to accommodate and display the book collection. A partial 1:2 scale mock-up, fabricated using the same robotic setup as the final installation, tested material behaviour, fabrication parameters, and assembly logic at near-architectural scale (Fig. 4). Each stage produced specific knowledge that informed subsequent decisions: the mock-up in particular revealed the importance of precise calibration, collision simulation, and toolpath control when working with large EPS modules and non-standard cutting frames. The full-scale 1:1 prototype was therefore not the starting point of the fabrication process but its conclusion, preceded by a structured sequence of material and spatial inquiry. 3.2 Robotic Fabrication: Workflow, Calibration and Material Response The fabrication workflow was built using a parametric model developed in Rhinoceros 3D and Grasshopper which enabled real-time manipulation of key geometric parameters including module dimensions, curvature and perforation patterns, allowing rapid exploration of design variations and iterative refinement (Woodbury, 2010 ). The project involved the shaping of 170 components cut from 97 EPS panels of 1000 × 1000 mm base and variable thickness (400 mm, 200 mm, and 100 mm), as detailed in Fig. 5. Robotic toolpaths were generated within the same environment using the KUKA|PRC plugin, which translated the geometric definition of each EPS panel into robotic instructions for hot-wire cutting, establishing a fully integrated digital fabrication workflow in which design generation and physical production share a continuous computational environment (Fig. 6) (Kolarevic, 2016 ). Two robotic configurations were calibrated to accommodate the working range required by the panel dimensions, with custom hot-wire frames designed and assembled by the research team in the absence of available commercial end-effectors for the required cutting span. Prior to cutting, toolpath simulations were used to identify potential collisions and verify fabrication sequences. A series of test cuts then enabled adjustment of robot position, wire temperature, and feed rate before advancing to full-scale production (Fig. 7). The material response of EPS was partially anticipated through preliminary testing and prior experience, and partially discovered through the fabrication process itself. Dimensional deviations of 5 to 10 mm, individually marginal, accumulated across the modular system and required continuous adjustment of toolpaths and cutting parameters. This feedback loop between computational model and material behaviour during cutting and assembly generated knowledge that simulation alone could not produce, and directly informed the implementation strategy described in the following section. A significant interoperability constraint also emerged during fabrication. A technical issue in the robotic laboratory required the research team to consider an alternative facility equipped with a different robotic system, which revealed a structural limitation in cross-compatibility among robotic fabrication systems: the KUKA Robot Language (KRL) controlling the fabrication process proved non-transferable to other platforms. The issue was ultimately resolved within the same laboratory, making the use of an alternative facility unnecessary. This episode nonetheless constitutes an empirical finding in its own right, with implications for the scalability and transferability of platform-specific computational workflows in robotic fabrication research. 3.3 Assembly, Logistics and on site adjustment Approximately one month prior to installation, the research team conducted an on-site survey to verify spatial constraints and identify potential discrepancies between the physical context and the final design. The project footprint was marked on the ground using yellow tape, after which a laser level and line measurer were used to verify site dimensions and ensure accurate positioning within the space. Transportation of the 170 EPS components required careful spatial planning: although lightweight, the material volume necessitated coordinated loading and handling to prevent damage. To facilitate transport and minimise the risk of damage, the cut components were reassembled into panels prior to loading. University facilities served as temporary storage and staging areas, and the assembly sequence was pre-planned to facilitate the workflow on site. The final implementation was complicated by the position of the site, which was at a lower elevation relative to the drop-off point, requiring manual transport of panels down an adjacent staircase. The operation involved a team of six people, organised in pairs, each carrying a set of four panels. An alphanumeric labelling system enabled accurate identification of components and prevented sequencing errors during assembly (Fig. 8). A laptop displaying the digital model was used to verify step by step the correspondence between the virtual geometry and the physical installation. The installation was completed in approximately 8 to 10 hours, involving a team of four people (Fig. 9). Construction proceeded from a fixed datum provided by a steel column supporting the existing canopy, with components glued using a specific adhesive for EPS and adjusted on site to manage accumulated tolerances. Following the installation, the waste material resulting from the cutting process was collected on site and transported to a local recycling facility. 4. Findings-Discussion 4.1 Material and Technical Knowledge The fabrication process generated material and technical knowledge that could not have been fully anticipated at the conceptual stage. As discussed in Section 3.2 , the sensitivity of EPS to variations in wire temperature, cutting speed, and block positioning required continuous empirical adjustment throughout the shaping of the panels. At the level of individual components, dimensional deviations of 5 to 10 mm were marginal, but their accumulation across the entire project necessitated on-site adjustments by the research team during construction. These deviations were not indicative of a failure of the computational workflow, but rather of the productive tension between digital precision and material behaviour: the adaptations required during installation generated practical knowledge about the relationship between parametric modelling and physical construction that simulation alone could not have produced (Fig. 10). In retrospect, the cutting sequence was not fully optimised, particularly in the library section where the geometry required a high number of cuts: a more systematic approach to cut positioning could have reduced tolerance accumulation and informed design decisions from the outset. In future applications, fabrication tolerances should be absorbed by the parametric model itself, with component geometry designed to accommodate predictable deviations rather than corrected during installation. The interoperability constraint encountered during fabrication constitutes a further technical finding. Although the issue was resolved within the same laboratory, it revealed a structural limitation in current robotic fabrication infrastructure: the dependency on platform-specific languages such as KRL conditions both the design process and the research outcomes in contexts where access to a specific robotic system cannot be guaranteed, pointing to the need for more flexible and platform-independent fabrication environments. The end-of-life management of EPS introduced a further dimension of material knowledge. At the early stage of the project, the research team contacted a local recycling facility to ensure that all components could be properly processed after the installation period. This step confirmed the feasibility of EPS recycling within the specific logistical conditions of Hong Kong, while also revealing the organisational effort required to align experimental architectural practice with principles of material sustainability. The volume of waste generated by the cutting process and the logistical requirements of recycling are factors that must be integrated into the planning of future EPS-based prototypes from the conceptual stage. Taken together, these findings demonstrate that technical and material knowledge in full-scale architectural prototyping is not fully anticipable: it emerges through the interaction between computational workflows, material behaviour, specific fabrication setup and on-site implementation. The most significant implication concerns the integration of fabrication tolerances into the parametric model itself: knowledge about how tolerances accumulate can only be gained through full-scale construction, and should subsequently inform the computational workflow from the outset rather than be corrected during on-site assembly. In addition, the geometry of individual components could be designed to anticipate and integrate the lines of junction between panels, treating them as part of the design (Fig. 11). This form of situated technical knowledge is accessible only through the act of making at full scale, and constitutes a primary contribution of prototyping as a research method. 4.2 Spatial Knowledge During the five-week installation period, LSCS revealed patterns of spatial occupation that no scaled model or digital simulation could have anticipated. While the prototyping sequence at 1:50, 1:5, and 1:2 scales had tested geometric configurations, structural behaviour, and fabrication parameters, spatial knowledge of this kind could only be generated through direct observation of how people interacted with the project and used the space over time (Schmidt & van Schaik, 2022 ). Spatial occupation was documented through systematic analysis of photographic records captured by two fixed cameras, positioned strategically to cover the space, at five-minute intervals. The aggregated map of the entire installation period shows that presence was distributed across different areas of the space, with persistent clustering along the library and exhibition areas on both weekdays and weekends, and stronger concentration in the seating area during weekend visits. This observed spatial differentiation constitutes knowledge about how this particular form, at this particular scale, within this particular urban context, organises collective spatial behaviour (Fig. 12). The map analysis reveals that occupation patterns were not stable across the five-week installation period. Initial weeks registered higher presence and more broadly distributed activity; a marked decline in the middle period, attributed by the research team to adverse weather conditions characteristic of Hong Kong's rainy season, was followed by an increase in visitor presence during the final weeks. No consistent pattern of use emerged across the entire period, suggesting that occupation was shaped by a combination of climatic, programmatic, and contextual factors rather than by spatial configuration alone. However, the positioning of the community library beneath the existing canopy proved to be an effective design decision: beyond protecting the book collection, the sheltered zone maintained a level of activity during periods of adverse weather that the more exposed areas of the installation could not support. The spatial configuration described in Section 3.1 , the curvilinear geometry, continuous surface, and visual permeability, was not simply a formal choice confirmed by use, but a condition that enabled these patterns of occupation. The layout of LSCS gave the space a dynamic character without creating isolated zones; the absence of fixed boundaries between programme areas allowed reading, socialising, and other activities to coexist naturally, while maintaining visual and physical permeability toward the adjacent streets and activating the interface between the installation and its urban context (Fig. 13). The findings described in this section demonstrate that spatial knowledge produced through in-situ prototyping is shaped by a combination of unpredictable and complex dynamics that a controlled research environment cannot replicate. As such, it constitutes a direct contribution to the research question guiding this study. 4.3 Social Knowledge Over the five-week installation period, the research team recorded approximately 250 visitors through a mixed-method framework combining photographic documentation and structured field observations. These data were complemented by a user perception questionnaire developed on the basis of the Public Space Index (PSI) introduced by Mehta ( 2014 ). The PSI assesses public space quality and user perception across five dimensions, inclusiveness, meaningfulness, safety, comfort, and pleasurability, and was conducted through structured survey sessions scheduled four times per week, covering different times of day from morning to evening, with two members of the research team present at each session to administer questionnaires and conduct direct field observation to complement the photographic data from the fixed cameras. A total of 47 questionnaires were collected across the five-week installation period, representing approximately 20% of the estimated total attendance; responses are treated as qualitative indicators of user perception rather than statistically representative findings. Based on the collected data, user perception indicated a high level of engagement with the space. 52% of respondents rated the space as "very attractive" and 72% as "very interesting". The feasibility of conducting activities and events was rated "in almost all" conditions by 72% of respondents. The space's capacity to support symbolically and culturally meaningful activities was rated "very much" or "moderately" by 80% of respondents, suggesting that the installation was perceived not merely as a physical intervention but as a culturally significant presence within the neighbourhood (Fig. 14). Discomfort attributable to the installation was reported as "none" by 68% and "very little" by 28% of respondents, indicating a high level of acceptance within the existing public space. The demographic profile of respondents indicated that the installation attracted a broad range of users. Respondents were predominantly female (60%), aged between 25 and 34 (36%), and of Chinese ethnicity (76%), with respondents drawn from Kowloon, the New Territories, and outside Hong Kong. 44% of respondents had not visited the site in the preceding twelve months, suggesting that the installation attracted users who did not habitually frequent the space. Primary activities reported included relaxing, reading, walking through the space, viewing the exhibition, and meeting friends, a range that extends beyond the passive rest typically associated with sitting-out areas in Hong Kong's dense urban fabric. It is important to note that the visitor count of approximately 250 should be understood as an estimate based on photographic records, while the 47 questionnaires form a sample reflecting user perceptions at selected moments during the installation period. The role of the community library as a social activator merits specific attention. With a collection of approximately 220 books operating on a self-managed exchange basis, the library encouraged active participation and a sense of shared ownership (Fig. 15). The involvement of the local NGO Phoboko, which organised a temporary photographic exhibition and periodic gatherings within LSCS, further reinforced the site's social activation, showing that community programming and local partnerships play a key role in sustaining and enhancing the use of a space over time. The analysis revealed how the prototype generates social knowledge that goes beyond the spatial configuration of the intervention: it actively promoted new patterns of collective use, attracted new users, and produced a measurable shift in the perceived cultural significance of the space (Fig. 16). This form of knowledge is accessible only through full-scale in-situ implementation over an extended period, and constitutes a direct contribution to the broader argument of this paper. 4.4 Institutional Knowledge The institutional dimensions of the LSCS project generated knowledge that could not have been anticipated through preliminary research into Hong Kong's public space governance framework. The prototype, by being implemented in an existing public space, revealed the epistemological significance of governance conditions that would otherwise remain invisible to architectural research. What the project revealed is that institutional frameworks governing public space in Hong Kong are not standardised, or fully understandable in advance: they must be navigated empirically, and the knowledge produced through that navigation is specific and situated. Although public open spaces in the city are predominantly administered by the Leisure and Cultural Services Department (LCSD), the Ladder Street Sitting Out Area fell under the jurisdiction of the Home Affairs Department (HAD), requiring engagement with a distinct administrative body whose regulatory framework for temporary installations was less formally defined. This revealed a significant difference in regulatory expertise that directly shaped the implementation process: LCSD has developed a detailed and well-established prescriptive framework for temporary installations, with precise parameters governing height, structural requirements, insurance, and programme. HAD, by contrast, administers only a limited number of public spaces in the city, and its officials were less familiar with the requirements applicable to temporary architectural interventions. During the meetings with HAD, the research team suggested applying the parameters established by LCSD as a reference framework to structure the design and implementation process of LSCS. This approach translated into a set of concrete design constraints. The 1.70-metre height limit, indicated by LCSD in previous installations, was applied in this project. This threshold, which became a constitutive parameter of the final geometry, represents the point beyond which more stringent safety procedures are required, including structural engineer approval. Similarly, the requirement to secure public liability insurance, standard practice under LCSD jurisdiction but not explicitly mentioned at the beginning of the process by HAD, was self-imposed by the research team to ensure adequate coverage for the installation area. The relative flexibility of HAD also extended to the duration of the project, affording the research team greater latitude than would typically be permitted under LCSD jurisdiction. A comparable occupation period was achieved in previous LCSD-managed projects, but required more formal negotiation to secure. This five-week period proved essential to generating the spatial and social knowledge documented in Sections 4.2 and 4.3 . Engaging empirically with this institutional landscape, through the actual process of seeking permissions, negotiating with officials, and managing compliance, produced knowledge about how public space is governed that preliminary research alone cannot access, and constitutes a distinct contribution of full-scale prototyping as a research-by-design method. 5 Concluding Remarks The article opened with Calvino's description of Sophronia as a conceptual lens through which to question conventional assumptions about permanence and temporality in the built environment. The LSCS project contributes to this reflection by illustrating how a short-term intervention can generate knowledge of lasting methodological relevance, suggesting that temporality is not a limitation of architectural research but a productive and exploratory condition. The central argument of this paper has been that full-scale architectural prototyping in public space functions as a research-by-design method capable of generating knowledge across four distinct but interrelated domains: technical, spatial, social, and institutional. The fabrication process produced material and technical knowledge that simulation could not have anticipated, concerning the behaviour of EPS under robotic hot-wire cutting, the management of fabrication tolerances, the limitations of platform-specific robotic infrastructure, and the logistical and assembly requirements of full-scale construction. The project also produced spatial knowledge about how a specific geometric configuration organises collective occupation over time, shaped by climatic, programmatic, and contextual conditions that scaled models cannot replicate. In turn, the five-week occupation of the site produced social knowledge about patterns of use and user perception, revealing a distinct set of dynamics that become visible only through direct interaction and occupation over an extended period. Finally, engagement with the administrative conditions of the site produced institutional knowledge about navigating public space governance in Hong Kong, including the management of different regulatory frameworks and compliance requirements. Taken together, these four domains constitute a response to the research question guiding this study: architectural prototyping in public space can function as a research-by-design method precisely because it is the condition of testing in a real urban context that makes this knowledge accessible, across technical, spatial, social, and institutional dimensions simultaneously. As is consistent with research-by-design, the findings of this study are situated and context-specific rather than statistically generalisable. As argued in the theoretical framework of this paper, LSCS operates across the two categories identified by Frayling ( 1993 ), research for design and research through design, in that the prototype constitutes a primary site of knowledge production, while the documentation of the fabrication process, spatial observations, and institutional negotiations makes that knowledge communicable beyond the work itself. As such, the prototype is a research instrument that activates real conditions, material, spatial, social, and regulatory, and produces knowledge through its engagement with those conditions over time. This resonates with Ferraris and Nimkulrat ( 2025 ), who argue that prototypes in research serve to identify problems, investigate issues, instigate debates, anticipate visions, and produce knowledge, enabling the translation of concepts from the abstract to the concrete. The project also confirms the feasibility of EPS as a material for temporary public installations when end-of-life management is integrated into the research process from the outset. However, the volume of material waste generated by the fabrication process and the logistical requirements of recycling exposed environmental and logistical challenges related to EPS, which echo broader critiques of non-biodegradable materials within computational design practices (Menges & Reichert, 2015 ), and point to the need for more systematic approaches to sustainable material practices in future prototype-based research. Recent work on bio-based and regenerative systems, including mycelium composites (Ross, 2021 ) and biophilic fabrication approaches (Bader & Oxman, 2016 ), suggests directions for future experimentation that could address these environmental limitations while extending the research agenda established here. More broadly, the LSCS advances a methodological agenda for practice-based architectural research in urban contexts: the development of replicable frameworks for full-scale prototyping that integrate technical and material research, spatial observation, social evaluation, and institutional negotiation as components of a single research instrument. The situated knowledge produced through this approach, specific and empirically grounded, represents a contribution to architectural research that only practice-based inquiry can generate, and aligns with broader efforts to establish design research as a legitimate mode of knowledge production within the discipline (Fraser, 2013 ). Temporality, in this account, is not a limitation of the research but its condition: it is precisely because the prototype was temporary, or in institutional terms non-permanent, that it could be implemented as a test in a real public space, under real institutional and material constraints, generating knowledge that extends beyond the academic sphere and directly impacts the experienced world. Declarations Declarations of generative AI and AI-assisted technologies in the manuscript preparation process: During the preparation of this work the author(s) used ChatGPT in order to proof read different sections of the manuscript. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the published article. Author Contribution F.R. and F.A. jointly conceptualised the research, developed the LSCS project, and conducted the on-site implementation and fieldwork. F.A. led the computational design and robotic fabrication workflow, while F.R. led the architectural and conceptual development of the intervention, with a specific focus on public space activation. Both authors contributed to data collection, analysis, and interpretation. They jointly wrote the manuscript text and prepared the figures. Both authors reviewed and approved the final manuscript. Acknowledgement The authors wish to thank the students and research assistants who contributed to the fabrication, installation, and fieldwork phases of the Ladder Street Cultural Space project. Their involvement in the robotic fabrication workflow, on-site assembly, behavioural observation, and administration of the user perception questionnaire was essential to the realisation and documentation of the research. The authors are also grateful to Phoboko for their collaboration during the five-week installation period, and in particular for organising the photographic exhibition and periodic community gatherings that contributed to the cultural activation of the space. Data Availability The datasets generated and analysed during the current study are not publicly available due to ethical restrictions concerning participant privacy. The data include photographic documentation of public space users and responses to a user perception questionnaire, collected under ethics clearance from the Chinese University of Hong Kong. Anonymised and aggregated data supporting the findings of this study are available from the corresponding author upon reasonable request. References Bader, C., & Oxman, N. (2016). Living matter: Towards the fabrication of microbial composites. In Proceedings of the 36th Annual Conference of the Association for Computer Aided Design in Architecture (ACADIA) (pp. 248–255). ACADIA. Biggs, M., & Büchler, D. (2008). Eight criteria for practice-based research in the creative and cultural industries. Art, Design & Communication in Higher Education, 7 (1), 5–18. Bishop, P., & Williams, L. (2012). The temporary city . Routledge. Braumann, J., & Brell-Cokcan, S. (2011). Parametric robot control: Integrated CAD/CAM for architectural design. In Proceedings of the 31st Annual Conference of the Association for Computer Aided Design in Architecture (ACADIA) (pp. 242–251). Association for Computer Aided Design in Architecture (ACADIA). Caetano, I., Leitão, A., & Santos, L. (2019). Computational design in architecture: Defining parametric, generative, and algorithmic design. In A. Sousa, J. P. Xavier, & G. Castro Henriques (Eds.), Architecture in the Age of the 4th Industrial Revolution: Proceedings of the 37th International Conference on Education and Research in Computer Aided Architectural Design in Europe (Vol. 3, pp. 157–166). eCAADe and SIGraDi. Caliari, P. F. (2000). La forma dell’effimero. Tra allestimento e architettura: compresenza di codici e sovrapposizione di tessiture . Lybra Immagine. Calvino, I. (2006). Invisible Cities (W. Weaver, Trans.). Harcourt. Cattiodoro, S. (2012). Il fondamento effimero dell’architettura . Aracne editrice. Coar, L. (2011). The lasting meaning in ephemeral architecture. Design Principles and Practices: An International Journal – Annual Review, 5 (6), 1–10. Cross, N. (2007). From a design science to a design discipline: Understanding designerly ways of knowing and thinking. In R. Michel (Ed.), Design Research Now (pp. 41–54). Birkhäuser. Diles, J. (2018). Lightweight stereotomy with glass-fiber reinforced plastic. Nexus Network Journal, 20 , 645–669. Ferraris, S. D., & Nimkulrat, N. (2025). Transitioning from abstractness to concreteness through prototyping. In N. Nimkulrat, S. D. Ferraris, & F. Mattioli (Eds.), Prototyping and experiential knowledge: Unfolding shifting views on the use of prototypes in design research (pp. 13–29). FrancoAngeli. Frayling, C. (1993). Research in art and design. Royal College of Art Research Papers, 1 (1). Royal College of Art. Fraser, M. (Ed.). (2013). Design research in architecture: An overview . Ashgate. Gritti, J. (2024). Ceremonies performed in public spaces: Ephemeral architecture and urban itineraries in Sforza Milan. Architectural Histories, 12 (1), 1–19. Jonas, W. (2007). Design and its meaning to the methodological development of the discipline. In R. Michel (Ed.), Design Research Now (pp. 187–206). Birkhäuser. Kannabiran, G., & Bødker, S. (2020). Prototypes as objects of desire. In DIS '20: Proceedings of the 2020 ACM Designing Interactive Systems Conference (pp. 1619–1631). ACM. https://doi.org/10.1145/3357236.3395487 Kolarevic, B. (2016). Digital fabrication: Architecture, art and craft . Thames & Hudson. Lim, Y.-K., Stolterman, E., & Tenenberg, J. (2008). The anatomy of prototypes: Prototypes as filters, prototypes as manifestations of design ideas. ACM Transactions on Computer-Human Interaction, 15(2), Article 7. Lim, Y. S., Izhar, T. N. T., Zakarya, I. A., Yusuf, S. Y., Zaaba, S. K., & Mohamad, M. A. (2021). Life cycle assessment of expanded polystyrene. IOP Conference Series: Earth and Environmental Science, 920 , Article 012030. Liotta, S.-J., & Louyot, F. (2022). Ephemeral architecture: Pavilion architecture as a tool to bridge academic research and professional practice. Practices in Research, 3 , 93–125. McGillivray, D., Guillard, S., Ross, G., & McCaughey, P. (2025). Participatory design practice, event(s) and the activation of public space. Journal of Urbanism: International Research on Placemaking and Urban Sustainability, 18 (4), 595–612. https://doi.org/10.1080/17549175.2023.2214140 Menges, A., & Reichert, S. (2015). Material capacity: Embedded responsiveness. Architectural Design, 85 (5), 44–53. Mehta, V. (2014). Evaluating Public Space. Journal of Urban Design, 19(1), 53–88. https://doi.org/10.1080/13574809.2013.854698 Naboni, R., Breseghello, L., & Kunic, A. (2019). Multi-scale design and fabrication of the Trabeculae Pavilion. Additive Manufacturing, 27 , 305–317. Park, S., Park, J. H., Jung, S., & Ji, S. J. (2022). Foam cutting for an architectural installation using industrial robot arm: Calibration, error, and deviation analysis. Automation in Construction, 135 , Article 104141. Rogers, Y. (2011). Interaction design gone wild: striving for wild theory. Interactions, 18(4), 58-62. doi:10.1145/1978822.1978834 Ross, P. (2021). Mycelium as a construction material. In S. T. A. Pickett, M. L. Cadenasso, B. P. McGrath, & M. M. Hill (Eds.), The Routledge companion to ecological design thinking (pp. 439–450). Routledge. Schmidt, L., & van Schaik, A. (2022). Emergent behaviors in urban prototyping: A framework for analyzing temporary interventions. Journal of Urban Design, 27 (4), 512–530. Schön, D. A. (1983). The Reflective Practitioner: How Professionals Think in Action . Routledge. https://doi.org/10.4324/9781315237473 Sulong, N. H. R., Mustapa, S. A. S., & Abdul Rashid, M. K. (2019). Application of expanded polystyrene (EPS) in buildings and constructions: A review. Journal of Applied Polymer Science, 136 (20), Article 47529. Tuncbilek, G. (2020). Experimentation in architecture: Pavilion design. Athens Journal of Architecture, 6 (4), 397–414. https://doi.org/10.30958/aja.6-4-5 Woodbury, R. (2010). Elements of parametric design . Routledge. Additional Declarations No competing interests reported. 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version.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Figure15.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9461708/v1/7f5df8af7f4a56606b9c12c7.jpg"},{"id":108808054,"identity":"15ca9d3e-ae0b-447f-97c1-f36a2b5b5dc1","added_by":"auto","created_at":"2026-05-08 15:39:33","extension":"jpg","order_by":16,"title":"Figure 16","display":"","copyAsset":false,"role":"figure","size":5253544,"visible":true,"origin":"","legend":"\u003cp\u003e\u0026nbsp;Legend not included with this version.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Figure16.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9461708/v1/b52362c83c929c9a58f09782.jpg"},{"id":108816865,"identity":"7e9a7493-8224-4fbe-be54-851da4311f8b","added_by":"auto","created_at":"2026-05-08 16:26:01","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":47386559,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9461708/v1/b0866fa9-cc00-4352-a0c4-b2088305f769.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Architectural Prototyping as Research-by-Design: Producing Situated Knowledge Through Temporary Public Interventions","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eIn \u003cem\u003eInvisible Cities\u003c/em\u003e, Italo Calvino (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) describes Sophronia as a city composed of two halves: one built of stone, marble and concrete; the other an amusement park of rides and entertainments. In the narrative, Calvino inverts the apparent logic of permanence: the stone city is periodically dismantled and moved, while the funfair remains. This incipit raises a question that frames the inquiry of this paper: how should we interpret permanence and temporality in the study of cities? The question opens a broader argument about temporality in architecture: not as a limiting condition, but as a productive one through which urban knowledge can be generated.\u003c/p\u003e \u003cp\u003eThe paper addresses the following research question: how can full-scale architectural prototyping function as a research-by-design method capable of generating material, spatial, social and institutional knowledge in an integrated manner? We argue that a prototype situated within the public realm is not simply a technical artefact to be evaluated for performance, but a research device that activates real conditions (regulatory, social and material) that remain inaccessible through simulation or conventional design development alone. This position extends existing frameworks for research-by-design (Sch\u0026ouml;n, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e1983\u003c/span\u003e; Cross, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2007\u003c/span\u003e) by treating the public space context as a constitutive dimension of the research rather than a neutral backdrop.\u003c/p\u003e \u003cp\u003eThe Ladder Street Cultural Space (LSCS) provides the empirical ground for this investigation: a temporary architectural installation developed for an underutilised sitting-out area in the Sheung Wan district of Hong Kong. Realised through a parametric computational workflow and robotic hot-wire cutting of Expanded Polystyrene (EPS) panels, the project operated at full scale for five weeks, integrating a community library, exhibition space and seating area. The choice of EPS was motivated by its suitability for robotic fabrication, its structural behaviour at architectural scale and the opportunity it offered to examine material performance, logistics and end-of-life management within a single experimental cycle.\u003c/p\u003e \u003cp\u003eThe paper articulates and empirically grounds a framework for understanding architectural prototyping in public space as an epistemic instrument, capable of generating knowledge across technical, spatial, social, and institutional domains in an integrated manner. This framework is developed through the LSCS project, which demonstrates how a full-scale temporary intervention in an underutilised urban space can simultaneously function as a fabrication research platform, a catalyst for social activation, and a means of revealing governance conditions that other research methods cannot easily access. The following sections present the theoretical context, the making process, and the findings of the LSCS, concluding with reflections on the implications of this approach for practice-based architectural research.\u003c/p\u003e"},{"header":"2. Research Context","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Temporality and Architectural Experimentation in Public Space\u003c/h2\u003e \u003cp\u003eTemporary architectural interventions provide a productive framework through which temporality can be explored as a design condition, translating time-limited processes into spatial, material and social configurations. Within rapidly evolving urban contexts, temporary urbanism has increasingly functioned as a flexible instrument for testing spatial strategies that permanent construction cannot accommodate. As Bishop and Williams (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2012\u003c/span\u003e) argue, temporary activities reflect a bottom-up current within contemporary society, through which people reappropriate urban space to suit emerging needs and lifestyles. Historically, ephemeral architecture has played a central role in shaping civic life, from Renaissance ceremonial arches and stage sets that translated collective rituals into spatial form (Gritti, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), to contemporary installations at events such as the Salone del Mobile or the Venice Architecture Biennale, contexts that offer opportunities to test unconventional materials, fabrication methods and spatial configurations under real conditions.\u003c/p\u003e \u003cp\u003eThe temporary nature of these interventions, structures that can be built and dismantled within a limited period of time, gives them the potential to attract broad public attention and media interest. In many cases they can be realised directly by the architects themselves, offering opportunities to explore construction methods and budgetary requirements as a way of searching for the new in both architectural practice and discourse (Tuncbilek, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Their limited duration enables experimentation, responsiveness and adaptation to shifting urban circumstances (Coar, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). These interventions transform existing urban spaces into temporary laboratories, reframing how people perceive and inhabit the city. As Cattiodoro (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2012\u003c/span\u003e) notes, the creative and technical expertise required to design temporary structures is as rigorous as that demanded by permanent architecture, with design processes frequently involving unconventional materials and fabrication methods that challenge established spatial conventions. Yet much of the discourse surrounding temporary architecture has emphasised symbolic, event-based or programmatic dimensions, inviting reflection on collective spatial practices (McGillivray et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2025\u003c/span\u003e), while less attention has been devoted to understanding how full-scale temporary interventions operate as research instruments embedded in governance frameworks, material constraints and fabrication processes.\u003c/p\u003e \u003cp\u003eWithin this expanded understanding, temporary architectural interventions can be reconsidered as epistemic devices, contexts in which design decisions, institutional regulation and material performance converge and mutually condition one another. This reframing positions architectural prototyping in public space not merely as spatial activation, but as a research-by-design practice grounded in the contingencies of real urban settings.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Research-by-Design and Prototyping as Knowledge Production\u003c/h2\u003e \u003cp\u003eResearch-by-design emerges from a broader reconceptualisation of design as a discipline of inquiry that extends beyond its practical dimension (Fraser, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). According to Sch\u0026ouml;n (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e1983\u003c/span\u003e), professional knowledge is not applied from theory to practice but generated within practice itself through cycles of action and reflection, a process he described as \u003cem\u003ereflection-in-action\u003c/em\u003e. This reframes design from a technical discipline to an epistemic one, in which knowledge is produced through making. Building on this, Cross (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2007\u003c/span\u003e) identified design as a specific way of knowing, distinct from scientific or humanistic inquiry. In this sense, architects and designers use drawings, models and prototypes as instruments through which ideas are developed, tested and revised. This explorative and iterative form of work generates new understanding by bringing concepts into physical form.\u003c/p\u003e \u003cp\u003eAccording to Frayling (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1993\u003c/span\u003e), design research can be understood as research \u003cem\u003einto\u003c/em\u003e, research \u003cem\u003ethrough\u003c/em\u003e, or research \u003cem\u003efor\u003c/em\u003e art and design, each implying a different relationship between practice and knowledge production. Research through design uses practice as a means of inquiry but requires explicit documentation of the process; research for design is that in which thinking is embodied in the artefact itself, communicable through visual or material form. Full-scale architectural prototyping as tested in LSCS operates across both categories: the artefact itself constitutes a primary element of knowledge production, while the documentation of the fabrication process, spatial observations and institutional negotiations makes that knowledge communicable beyond the work itself. Prototypes, as argued by Lim et al. (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2008\u003c/span\u003e), are instruments for exploring a design concept: they isolate specific qualities, give them physical form, and enable reflection that abstract thinking alone cannot support, while also testing decisions shaped by external constraints, whether material, spatial, or regulatory. As Kannabiran and B\u0026oslash;dker (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) observe, different prototyping techniques enable different modes of inquiry, with varied intentions and outcomes.\u003c/p\u003e \u003cp\u003eThis body of work has considerably advanced understanding of prototyping as an epistemic practice within design research, and recent scholarship continues to expand its scope across disciplinary contexts (Ferraris \u0026amp; Nimkulrat, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). However, the majority of these frameworks have been developed in relation to controlled studio environments, scaled models, and digital or product design contexts. Full-scale architectural prototypes deployed in real public space for extended periods, structured as deliberate research instruments rather than event-driven pop-up interventions, remain comparatively rare in the literature. This relative lack of examples reflects institutional conditions such as limited research funding and persistent scepticism toward practice-based inquiry in architectural academia, rooted in part in what Jonas (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2007\u003c/span\u003e) describes as the still weak epistemological status of research-through-design as a mode of knowledge production. It also raises methodological concerns about the difficulty of making the designer's decision-making process sufficiently transparent, given that design research requires explicit documentation and communication of results in re-usable form (Cross, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), and the inherent ambiguity between professional practice and research activity (Biggs \u0026amp; B\u0026uuml;chler, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTo these established limitations, architectural prototyping implemented in a real urban context adds a further layer of operational complexity that studio-based research does not encounter: negotiating safety requirements, institutional permissions, and civic responsibilities introduces constraints that directly shape the research process and outcomes (Liotta \u0026amp; Louyot, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). This approach resonates with what Rogers (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) describes as prototyping in the wild, evaluating design interventions in situ rather than in controlled settings, here transposed from interaction design to the context of full-scale architectural research. Design decisions emerge from and respond to particular socio-spatial and regulatory conditions, producing knowledge that is situated rather than generic. This site-specificity is not a methodological limitation but an epistemically productive condition: a prototype embedded in a real urban context generates knowledge about material performance, spatial occupation, and institutional governance that controlled research settings cannot access.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Digital Fabrication and Material Performance in Architectural Research\u003c/h2\u003e \u003cp\u003eIn recent decades, computational design and robotic fabrication have emerged as key drivers of innovation in architectural production, enabling the generation of complex geometries and more adaptive design processes (Caetano et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Within experimental and temporary architecture, these tools have evolved into accessible platforms that support architects in managing increasing levels of complexity, establishing a direct link between design generation and fabrication logic (Braumann \u0026amp; Brell-Cokcan, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Parametric modelling has expanded traditional design approaches by enabling real-time manipulation of geometric parameters, rapid exploration of design variations, and iterative refinement, conditions that are particularly productive in research contexts where the design-to-fabrication process is itself an object of inquiry (Naboni et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe field of robotic fabrication has advanced considerably with the emergence of parametric robot-control software that integrates design generation and fabrication logic within unified workflows, streamlining the translation from digital models to physical production. Among these tools, KUKA|PRC, a plugin developed for visual programming environments, exemplifies this shift by directly linking computational modelling with robotic execution, and was adopted as the primary design-to-fabrication platform for the LSCS project. Within such workflows, material properties directly condition the fabrication process: as Menges and Reichert (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) argue, materials embed characteristics that condition fabrication strategies, geometric possibilities, and spatial outcomes, becoming active parameters in the design process. In research-by-design practice, the constraints introduced by materials within a computational workflow become an opportunity to generate empirical knowledge that extends beyond what simulation alone can achieve.\u003c/p\u003e \u003cp\u003eExpanded Polystyrene (EPS) exemplifies this dynamic. Characterised by a lightweight yet rigid structure composed of approximately 98% air, EPS offers high impact resistance, structural stability, and precise shapeability through robotic hot-wire cutting, which enables the fabrication of complex three-dimensional geometries at architectural scale (Park et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Sulong et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Its sensitivity to temperature, cutting speed, and wire tension means that material behaviour and computational precision interact continuously throughout fabrication, requiring calibration and generating knowledge that cannot be fully anticipated at the modelling stage. Precedents such as Kwangho Lee's EPS Grotto (2014) and Plasticity Pavilion by Justin Diles demonstrate how EPS can serve as a medium for investigating tectonic, structural, and experiential dimensions of architectural form beyond its conventional applications (Diles, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), an approach that directly informed the development of LSCS. Despite its advantages for experimental fabrication, EPS raises environmental concerns related to plastic waste; when properly managed and recycled, however, its impact can be substantially reduced (Lim et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the LSCS project, the integration of parametric modelling and robotic hot-wire cutting created a direct link between the design process, geometric definition, and material behaviour. Rather than simply automating production, this configuration made the design-to-fabrication process a research instrument through which knowledge about EPS performance, fabrication tolerances, and spatial outcomes was generated progressively during making.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Making process","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Design Approach and Prototyping Strategy\u003c/h2\u003e \u003cp\u003eThe LSCS project was developed for a small sitting-out area in the Sheung Wan district of Hong Kong, a neighbourhood characterised by antique shops, art galleries, and a mixed demographic of residents and tourists. The site was underutilised and not integrated into the pedestrian flows and surrounding urban fabric. The intervention aimed to increase its visibility and activate collective use through a distinctive architectural presence capable of drawing attention from adjacent streets.\u003c/p\u003e \u003cp\u003eThe programme integrated three functions: a community library, an exhibition space, and a seating area. Rather than treating these as separate zones, the design sought spatial continuity between them, supporting multiple forms of use and collective engagement. The spatial organisation of the programme took into account a range of site-specific factors, including topography, pedestrian flows, and the presence of an existing canopy, which informed the positioning of the library within the sheltered area of the space (Fig.\u0026nbsp;1).\u003c/p\u003e \u003cp\u003eThe geometry was derived from a series of interlocking circles, producing curvilinear forms that generate smooth transitions between functional areas and a more dynamic spatial experience (Fig.\u0026nbsp;2). This configuration was also expected to introduce structural advantages over planar vertical surfaces: load distribution along continuous paths improves resistance to wind pressure and dynamic interaction forces (Fig.\u0026nbsp;3).\u003c/p\u003e \u003cp\u003eThe design process was structured as a progressive prototyping sequence operating across four scales. Initial 1:50 models evaluated the overall spatial configuration and the relationship between the installation and its urban context. A 1:5 three-dimensional printed model investigated the complex geometries of the installation, including those requireed to accommodate and display the book collection.\u003c/p\u003e \u003cp\u003eA partial 1:2 scale mock-up, fabricated using the same robotic setup as the final installation, tested material behaviour, fabrication parameters, and assembly logic at near-architectural scale (Fig.\u0026nbsp;4). Each stage produced specific knowledge that informed subsequent decisions: the mock-up in particular revealed the importance of precise calibration, collision simulation, and toolpath control when working with large EPS modules and non-standard cutting frames. The full-scale 1:1 prototype was therefore not the starting point of the fabrication process but its conclusion, preceded by a structured sequence of material and spatial inquiry.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Robotic Fabrication: Workflow, Calibration and Material Response\u003c/h2\u003e \u003cp\u003eThe fabrication workflow was built using a parametric model developed in Rhinoceros 3D and Grasshopper which enabled real-time manipulation of key geometric parameters including module dimensions, curvature and perforation patterns, allowing rapid exploration of design variations and iterative refinement (Woodbury, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). The project involved the shaping of 170 components cut from 97 EPS panels of 1000 \u0026times; 1000 mm base and variable thickness (400 mm, 200 mm, and 100 mm), as detailed in Fig.\u0026nbsp;5. Robotic toolpaths were generated within the same environment using the KUKA|PRC plugin, which translated the geometric definition of each EPS panel into robotic instructions for hot-wire cutting, establishing a fully integrated digital fabrication workflow in which design generation and physical production share a continuous computational environment (Fig.\u0026nbsp;6) (Kolarevic, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTwo robotic configurations were calibrated to accommodate the working range required by the panel dimensions, with custom hot-wire frames designed and assembled by the research team in the absence of available commercial end-effectors for the required cutting span. Prior to cutting, toolpath simulations were used to identify potential collisions and verify fabrication sequences. A series of test cuts then enabled adjustment of robot position, wire temperature, and feed rate before advancing to full-scale production (Fig.\u0026nbsp;7).\u003c/p\u003e \u003cp\u003eThe material response of EPS was partially anticipated through preliminary testing and prior experience, and partially discovered through the fabrication process itself. Dimensional deviations of 5 to 10 mm, individually marginal, accumulated across the modular system and required continuous adjustment of toolpaths and cutting parameters. This feedback loop between computational model and material behaviour during cutting and assembly generated knowledge that simulation alone could not produce, and directly informed the implementation strategy described in the following section.\u003c/p\u003e \u003cp\u003eA significant interoperability constraint also emerged during fabrication. A technical issue in the robotic laboratory required the research team to consider an alternative facility equipped with a different robotic system, which revealed a structural limitation in cross-compatibility among robotic fabrication systems: the KUKA Robot Language (KRL) controlling the fabrication process proved non-transferable to other platforms. The issue was ultimately resolved within the same laboratory, making the use of an alternative facility unnecessary. This episode nonetheless constitutes an empirical finding in its own right, with implications for the scalability and transferability of platform-specific computational workflows in robotic fabrication research.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Assembly, Logistics and on site adjustment\u003c/h2\u003e \u003cp\u003eApproximately one month prior to installation, the research team conducted an on-site survey to verify spatial constraints and identify potential discrepancies between the physical context and the final design. The project footprint was marked on the ground using yellow tape, after which a laser level and line measurer were used to verify site dimensions and ensure accurate positioning within the space. Transportation of the 170 EPS components required careful spatial planning: although lightweight, the material volume necessitated coordinated loading and handling to prevent damage. To facilitate transport and minimise the risk of damage, the cut components were reassembled into panels prior to loading. University facilities served as temporary storage and staging areas, and the assembly sequence was pre-planned to facilitate the workflow on site.\u003c/p\u003e \u003cp\u003eThe final implementation was complicated by the position of the site, which was at a lower elevation relative to the drop-off point, requiring manual transport of panels down an adjacent staircase. The operation involved a team of six people, organised in pairs, each carrying a set of four panels. An alphanumeric labelling system enabled accurate identification of components and prevented sequencing errors during assembly (Fig.\u0026nbsp;8).\u003c/p\u003e \u003cp\u003eA laptop displaying the digital model was used to verify step by step the correspondence between the virtual geometry and the physical installation. The installation was completed in approximately 8 to 10 hours, involving a team of four people (Fig.\u0026nbsp;9). Construction proceeded from a fixed datum provided by a steel column supporting the existing canopy, with components glued using a specific adhesive for EPS and adjusted on site to manage accumulated tolerances. Following the installation, the waste material resulting from the cutting process was collected on site and transported to a local recycling facility.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Findings-Discussion","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Material and Technical Knowledge\u003c/h2\u003e \u003cp\u003eThe fabrication process generated material and technical knowledge that could not have been fully anticipated at the conceptual stage. As discussed in Section \u003cspan refid=\"Sec8\" class=\"InternalRef\"\u003e3.2\u003c/span\u003e, the sensitivity of EPS to variations in wire temperature, cutting speed, and block positioning required continuous empirical adjustment throughout the shaping of the panels. At the level of individual components, dimensional deviations of 5 to 10 mm were marginal, but their accumulation across the entire project necessitated on-site adjustments by the research team during construction. These deviations were not indicative of a failure of the computational workflow, but rather of the productive tension between digital precision and material behaviour: the adaptations required during installation generated practical knowledge about the relationship between parametric modelling and physical construction that simulation alone could not have produced (Fig.\u0026nbsp;10).\u003c/p\u003e \u003cp\u003eIn retrospect, the cutting sequence was not fully optimised, particularly in the library section where the geometry required a high number of cuts: a more systematic approach to cut positioning could have reduced tolerance accumulation and informed design decisions from the outset. In future applications, fabrication tolerances should be absorbed by the parametric model itself, with component geometry designed to accommodate predictable deviations rather than corrected during installation.\u003c/p\u003e \u003cp\u003eThe interoperability constraint encountered during fabrication constitutes a further technical finding. Although the issue was resolved within the same laboratory, it revealed a structural limitation in current robotic fabrication infrastructure: the dependency on platform-specific languages such as KRL conditions both the design process and the research outcomes in contexts where access to a specific robotic system cannot be guaranteed, pointing to the need for more flexible and platform-independent fabrication environments.\u003c/p\u003e \u003cp\u003eThe end-of-life management of EPS introduced a further dimension of material knowledge. At the early stage of the project, the research team contacted a local recycling facility to ensure that all components could be properly processed after the installation period. This step confirmed the feasibility of EPS recycling within the specific logistical conditions of Hong Kong, while also revealing the organisational effort required to align experimental architectural practice with principles of material sustainability. The volume of waste generated by the cutting process and the logistical requirements of recycling are factors that must be integrated into the planning of future EPS-based prototypes from the conceptual stage.\u003c/p\u003e \u003cp\u003eTaken together, these findings demonstrate that technical and material knowledge in full-scale architectural prototyping is not fully anticipable: it emerges through the interaction between computational workflows, material behaviour, specific fabrication setup and on-site implementation. The most significant implication concerns the integration of fabrication tolerances into the parametric model itself: knowledge about how tolerances accumulate can only be gained through full-scale construction, and should subsequently inform the computational workflow from the outset rather than be corrected during on-site assembly. In addition, the geometry of individual components could be designed to anticipate and integrate the lines of junction between panels, treating them as part of the design (Fig.\u0026nbsp;11). This form of situated technical knowledge is accessible only through the act of making at full scale, and constitutes a primary contribution of prototyping as a research method.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Spatial Knowledge\u003c/h2\u003e \u003cp\u003eDuring the five-week installation period, LSCS revealed patterns of spatial occupation that no scaled model or digital simulation could have anticipated. While the prototyping sequence at 1:50, 1:5, and 1:2 scales had tested geometric configurations, structural behaviour, and fabrication parameters, spatial knowledge of this kind could only be generated through direct observation of how people interacted with the project and used the space over time (Schmidt \u0026amp; van Schaik, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSpatial occupation was documented through systematic analysis of photographic records captured by two fixed cameras, positioned strategically to cover the space, at five-minute intervals. The aggregated map of the entire installation period shows that presence was distributed across different areas of the space, with persistent clustering along the library and exhibition areas on both weekdays and weekends, and stronger concentration in the seating area during weekend visits. This observed spatial differentiation constitutes knowledge about how this particular form, at this particular scale, within this particular urban context, organises collective spatial behaviour (Fig.\u0026nbsp;12).\u003c/p\u003e \u003cp\u003eThe map analysis reveals that occupation patterns were not stable across the five-week installation period. Initial weeks registered higher presence and more broadly distributed activity; a marked decline in the middle period, attributed by the research team to adverse weather conditions characteristic of Hong Kong's rainy season, was followed by an increase in visitor presence during the final weeks. No consistent pattern of use emerged across the entire period, suggesting that occupation was shaped by a combination of climatic, programmatic, and contextual factors rather than by spatial configuration alone. However, the positioning of the community library beneath the existing canopy proved to be an effective design decision: beyond protecting the book collection, the sheltered zone maintained a level of activity during periods of adverse weather that the more exposed areas of the installation could not support.\u003c/p\u003e \u003cp\u003eThe spatial configuration described in Section \u003cspan refid=\"Sec7\" class=\"InternalRef\"\u003e3.1\u003c/span\u003e, the curvilinear geometry, continuous surface, and visual permeability, was not simply a formal choice confirmed by use, but a condition that enabled these patterns of occupation. The layout of LSCS gave the space a dynamic character without creating isolated zones; the absence of fixed boundaries between programme areas allowed reading, socialising, and other activities to coexist naturally, while maintaining visual and physical permeability toward the adjacent streets and activating the interface between the installation and its urban context (Fig.\u0026nbsp;13).\u003c/p\u003e \u003cp\u003eThe findings described in this section demonstrate that spatial knowledge produced through in-situ prototyping is shaped by a combination of unpredictable and complex dynamics that a controlled research environment cannot replicate. As such, it constitutes a direct contribution to the research question guiding this study.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e4.3 Social Knowledge\u003c/h2\u003e \u003cp\u003eOver the five-week installation period, the research team recorded approximately 250 visitors through a mixed-method framework combining photographic documentation and structured field observations. These data were complemented by a user perception questionnaire developed on the basis of the Public Space Index (PSI) introduced by Mehta (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). The PSI assesses public space quality and user perception across five dimensions, inclusiveness, meaningfulness, safety, comfort, and pleasurability, and was conducted through structured survey sessions scheduled four times per week, covering different times of day from morning to evening, with two members of the research team present at each session to administer questionnaires and conduct direct field observation to complement the photographic data from the fixed cameras. A total of 47 questionnaires were collected across the five-week installation period, representing approximately 20% of the estimated total attendance; responses are treated as qualitative indicators of user perception rather than statistically representative findings.\u003c/p\u003e \u003cp\u003eBased on the collected data, user perception indicated a high level of engagement with the space. 52% of respondents rated the space as \"very attractive\" and 72% as \"very interesting\". The feasibility of conducting activities and events was rated \"in almost all\" conditions by 72% of respondents. The space's capacity to support symbolically and culturally meaningful activities was rated \"very much\" or \"moderately\" by 80% of respondents, suggesting that the installation was perceived not merely as a physical intervention but as a culturally significant presence within the neighbourhood (Fig.\u0026nbsp;14). Discomfort attributable to the installation was reported as \"none\" by 68% and \"very little\" by 28% of respondents, indicating a high level of acceptance within the existing public space.\u003c/p\u003e \u003cp\u003eThe demographic profile of respondents indicated that the installation attracted a broad range of users. Respondents were predominantly female (60%), aged between 25 and 34 (36%), and of Chinese ethnicity (76%), with respondents drawn from Kowloon, the New Territories, and outside Hong Kong. 44% of respondents had not visited the site in the preceding twelve months, suggesting that the installation attracted users who did not habitually frequent the space. Primary activities reported included relaxing, reading, walking through the space, viewing the exhibition, and meeting friends, a range that extends beyond the passive rest typically associated with sitting-out areas in Hong Kong's dense urban fabric.\u003c/p\u003e \u003cp\u003eIt is important to note that the visitor count of approximately 250 should be understood as an estimate based on photographic records, while the 47 questionnaires form a sample reflecting user perceptions at selected moments during the installation period. The role of the community library as a social activator merits specific attention. With a collection of approximately 220 books operating on a self-managed exchange basis, the library encouraged active participation and a sense of shared ownership (Fig.\u0026nbsp;15).\u003c/p\u003e \u003cp\u003eThe involvement of the local NGO Phoboko, which organised a temporary photographic exhibition and periodic gatherings within LSCS, further reinforced the site's social activation, showing that community programming and local partnerships play a key role in sustaining and enhancing the use of a space over time. The analysis revealed how the prototype generates social knowledge that goes beyond the spatial configuration of the intervention: it actively promoted new patterns of collective use, attracted new users, and produced a measurable shift in the perceived cultural significance of the space (Fig.\u0026nbsp;16). This form of knowledge is accessible only through full-scale in-situ implementation over an extended period, and constitutes a direct contribution to the broader argument of this paper.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e4.4 Institutional Knowledge\u003c/h2\u003e \u003cp\u003eThe institutional dimensions of the LSCS project generated knowledge that could not have been anticipated through preliminary research into Hong Kong's public space governance framework. The prototype, by being implemented in an existing public space, revealed the epistemological significance of governance conditions that would otherwise remain invisible to architectural research. What the project revealed is that institutional frameworks governing public space in Hong Kong are not standardised, or fully understandable in advance: they must be navigated empirically, and the knowledge produced through that navigation is specific and situated.\u003c/p\u003e \u003cp\u003eAlthough public open spaces in the city are predominantly administered by the Leisure and Cultural Services Department (LCSD), the Ladder Street Sitting Out Area fell under the jurisdiction of the Home Affairs Department (HAD), requiring engagement with a distinct administrative body whose regulatory framework for temporary installations was less formally defined. This revealed a significant difference in regulatory expertise that directly shaped the implementation process: LCSD has developed a detailed and well-established prescriptive framework for temporary installations, with precise parameters governing height, structural requirements, insurance, and programme. HAD, by contrast, administers only a limited number of public spaces in the city, and its officials were less familiar with the requirements applicable to temporary architectural interventions.\u003c/p\u003e \u003cp\u003eDuring the meetings with HAD, the research team suggested applying the parameters established by LCSD as a reference framework to structure the design and implementation process of LSCS. This approach translated into a set of concrete design constraints. The 1.70-metre height limit, indicated by LCSD in previous installations, was applied in this project. This threshold, which became a constitutive parameter of the final geometry, represents the point beyond which more stringent safety procedures are required, including structural engineer approval. Similarly, the requirement to secure public liability insurance, standard practice under LCSD jurisdiction but not explicitly mentioned at the beginning of the process by HAD, was self-imposed by the research team to ensure adequate coverage for the installation area.\u003c/p\u003e \u003cp\u003eThe relative flexibility of HAD also extended to the duration of the project, affording the research team greater latitude than would typically be permitted under LCSD jurisdiction. A comparable occupation period was achieved in previous LCSD-managed projects, but required more formal negotiation to secure. This five-week period proved essential to generating the spatial and social knowledge documented in Sections \u003cspan refid=\"Sec12\" class=\"InternalRef\"\u003e4.2\u003c/span\u003e and \u003cspan refid=\"Sec13\" class=\"InternalRef\"\u003e4.3\u003c/span\u003e. Engaging empirically with this institutional landscape, through the actual process of seeking permissions, negotiating with officials, and managing compliance, produced knowledge about how public space is governed that preliminary research alone cannot access, and constitutes a distinct contribution of full-scale prototyping as a research-by-design method.\u003c/p\u003e \u003c/div\u003e"},{"header":"5 Concluding Remarks","content":"\u003cp\u003eThe article opened with Calvino's description of Sophronia as a conceptual lens through which to question conventional assumptions about permanence and temporality in the built environment. The LSCS project contributes to this reflection by illustrating how a short-term intervention can generate knowledge of lasting methodological relevance, suggesting that temporality is not a limitation of architectural research but a productive and exploratory condition.\u003c/p\u003e \u003cp\u003eThe central argument of this paper has been that full-scale architectural prototyping in public space functions as a research-by-design method capable of generating knowledge across four distinct but interrelated domains: technical, spatial, social, and institutional. The fabrication process produced material and technical knowledge that simulation could not have anticipated, concerning the behaviour of EPS under robotic hot-wire cutting, the management of fabrication tolerances, the limitations of platform-specific robotic infrastructure, and the logistical and assembly requirements of full-scale construction. The project also produced spatial knowledge about how a specific geometric configuration organises collective occupation over time, shaped by climatic, programmatic, and contextual conditions that scaled models cannot replicate. In turn, the five-week occupation of the site produced social knowledge about patterns of use and user perception, revealing a distinct set of dynamics that become visible only through direct interaction and occupation over an extended period. Finally, engagement with the administrative conditions of the site produced institutional knowledge about navigating public space governance in Hong Kong, including the management of different regulatory frameworks and compliance requirements.\u003c/p\u003e \u003cp\u003eTaken together, these four domains constitute a response to the research question guiding this study: architectural prototyping in public space can function as a research-by-design method precisely because it is the condition of testing in a real urban context that makes this knowledge accessible, across technical, spatial, social, and institutional dimensions simultaneously. As is consistent with research-by-design, the findings of this study are situated and context-specific rather than statistically generalisable.\u003c/p\u003e \u003cp\u003eAs argued in the theoretical framework of this paper, LSCS operates across the two categories identified by Frayling (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1993\u003c/span\u003e), research \u003cem\u003efor\u003c/em\u003e design and research \u003cem\u003ethrough\u003c/em\u003e design, in that the prototype constitutes a primary site of knowledge production, while the documentation of the fabrication process, spatial observations, and institutional negotiations makes that knowledge communicable beyond the work itself. As such, the prototype is a research instrument that activates real conditions, material, spatial, social, and regulatory, and produces knowledge through its engagement with those conditions over time. This resonates with Ferraris and Nimkulrat (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2025\u003c/span\u003e), who argue that prototypes in research serve to identify problems, investigate issues, instigate debates, anticipate visions, and produce knowledge, enabling the translation of concepts from the abstract to the concrete.\u003c/p\u003e \u003cp\u003eThe project also confirms the feasibility of EPS as a material for temporary public installations when end-of-life management is integrated into the research process from the outset. However, the volume of material waste generated by the fabrication process and the logistical requirements of recycling exposed environmental and logistical challenges related to EPS, which echo broader critiques of non-biodegradable materials within computational design practices (Menges \u0026amp; Reichert, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), and point to the need for more systematic approaches to sustainable material practices in future prototype-based research. Recent work on bio-based and regenerative systems, including mycelium composites (Ross, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) and biophilic fabrication approaches (Bader \u0026amp; Oxman, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), suggests directions for future experimentation that could address these environmental limitations while extending the research agenda established here.\u003c/p\u003e \u003cp\u003eMore broadly, the LSCS advances a methodological agenda for practice-based architectural research in urban contexts: the development of replicable frameworks for full-scale prototyping that integrate technical and material research, spatial observation, social evaluation, and institutional negotiation as components of a single research instrument. The situated knowledge produced through this approach, specific and empirically grounded, represents a contribution to architectural research that only practice-based inquiry can generate, and aligns with broader efforts to establish design research as a legitimate mode of knowledge production within the discipline (Fraser, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTemporality, in this account, is not a limitation of the research but its condition: it is precisely because the prototype was temporary, or in institutional terms non-permanent, that it could be implemented as a test in a real public space, under real institutional and material constraints, generating knowledge that extends beyond the academic sphere and directly impacts the experienced world.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eDeclarations of generative AI and AI-assisted technologies in the manuscript preparation process:\u003c/h2\u003e\n\u003cp\u003eDuring the preparation of this work the author(s) used ChatGPT in order to proof read different sections of the manuscript. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the published article.\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eF.R. and F.A. jointly conceptualised the research, developed the LSCS project, and conducted the on-site implementation and fieldwork. F.A. led the computational design and robotic fabrication workflow, while F.R. led the architectural and conceptual development of the intervention, with a specific focus on public space activation. Both authors contributed to data collection, analysis, and interpretation. They jointly wrote the manuscript text and prepared the figures. Both authors reviewed and approved the final manuscript.\u003c/p\u003e\n\u003ch2\u003eAcknowledgement\u003c/h2\u003e\n\u003cp\u003eThe authors wish to thank the students and research assistants who contributed to the fabrication, installation, and fieldwork phases of the Ladder Street Cultural Space project. Their involvement in the robotic fabrication workflow, on-site assembly, behavioural observation, and administration of the user perception questionnaire was essential to the realisation and documentation of the research. The authors are also grateful to Phoboko for their collaboration during the five-week installation period, and in particular for organising the photographic exhibition and periodic community gatherings that contributed to the cultural activation of the space.\u003c/p\u003e\n\u003ch2\u003eData Availability\u003c/h2\u003e\n\u003cp\u003eThe datasets generated and analysed during the current study are not publicly available due to ethical restrictions concerning participant privacy. The data include photographic documentation of public space users and responses to a user perception questionnaire, collected under ethics clearance from the Chinese University of Hong Kong. Anonymised and aggregated data supporting the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBader, C., \u0026amp; Oxman, N. (2016). Living matter: Towards the fabrication of microbial composites. 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Application of expanded polystyrene (EPS) in buildings and constructions: A review. \u003cem\u003eJournal of Applied Polymer Science, 136\u003c/em\u003e(20), Article 47529.\u003c/li\u003e\n\u003cli\u003eTuncbilek, G. (2020). Experimentation in architecture: Pavilion design. \u003cem\u003eAthens Journal of Architecture, 6\u003c/em\u003e(4), 397\u0026ndash;414. https://doi.org/10.30958/aja.6-4-5\u003c/li\u003e\n\u003cli\u003eWoodbury, R. (2010). \u003cem\u003eElements of parametric design\u003c/em\u003e. Routledge. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Architecture Prototypes, Research-by-Design, Temporary Urban Interventions, Robotic Fabrication, Public Space Activationù","lastPublishedDoi":"10.21203/rs.3.rs-9461708/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9461708/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis paper investigates how full-scale architectural prototyping can function as a research-by-design method for generating integrated knowledge through implementation in real urban conditions. The argument is developed through the Ladder Street Cultural Space (LSCS), a temporary project realised for five weeks in an underutilised sitting-out area in one of Hong Kong's oldest districts. Fabricated in Expanded Polystyrene (EPS) panels through parametric computational design methods, the project integrated a community library, an exhibition space, and a seating area. LSCS is part of a broader research investigation on how to reactivate underutilised open spaces in high-density cities.\u003c/p\u003e \u003cp\u003eThe article argues that an architectural prototype situated within the public realm constitutes a research device that activates regulatory, social, and material conditions, generating knowledge that other research methods cannot easily produce. Extending existing frameworks for research-by-design, it treats the public space context as a constitutive dimension of the research rather than a neutral backdrop.\u003c/p\u003e \u003cp\u003eFindings demonstrate that LSCS revealed how a specific geometric configuration organises collective occupation, activating new patterns of social use and community engagement, and how public space governance frameworks in Hong Kong shape the spatial conditions and implementation, while also confirming the active role of materiality and fabrication processes in shaping design decisions. Although site-specific, these findings ground a methodological framework transferable to other urban contexts.\u003c/p\u003e \u003cp\u003eThe paper advances a methodological agenda for practice-based architectural research in urban contexts, in which temporality is not a limitation but a productive condition of inquiry.\u003c/p\u003e","manuscriptTitle":"Architectural Prototyping as Research-by-Design: Producing Situated Knowledge Through Temporary Public Interventions","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-07 06:52:06","doi":"10.21203/rs.3.rs-9461708/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fe281f20-82b8-4150-9c4a-90af580ce6e1","owner":[],"postedDate":"May 7th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-07T06:52:06+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-07 06:52:06","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9461708","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9461708","identity":"rs-9461708","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}