Exploring the Effectiveness of Co-Located Immersive Virtual Reality Experience for Co-Design of Urban Public Spaces: Case Study of the Eindhoven Station Square

Abstract

Enhancing urban public spaces (UPS) is vital for the well-being of their users. This study investigates the use of co-located immersive virtual reality (IVR) in a co-design process with potential end-users, focusing on active design generation and collaboration. Eindhoven station square, poised for significant redevelopment, served as the case study. An immersive experiment setup, through an altered off-the-shelf IVR application, was used. Participants were tasked with collaboratively designing the area, considering attributes like trees, parking, benches, shelter, and a fountain. Each session involved two participants with distinct perspectives, one from a local authority and the other from an end-user. Twenty participants, divided into ten sessions, engaged in the study. Most had no prior co-design or IVR experience but found the process and the altered application suitable. Communication primarily focused on design generation rather than tool usability or unrelated social exchanges, indicating that the co-located IVR experience resulted in engaged task participation. Most participants were willing to attend a co-design session if IVR would be used. The co-located immersive experience enhanced their understanding and confidence in design choices, indicating effective collaboration. This study concludes that non-experts can successfully engage in UPS design when simultaneously immersed and collocated using IVR. Future experiments should limit session duration to 30 min to avoid fatigue and ensure communication.

1. Introduction

Urban public spaces (UPS) play a vital role in enhancing citizens’ well-being and health by promoting physical activity and social interaction and by contributing to environmental sustainability. The design of these spaces, including key elements such as trees, seating, shelters, and parking, directly impacts their functionality and aesthetic appeal [1,2]. However, traditional urban design approaches often overlook the participation of end-users, leading to spaces that may not fully meet diverse community needs.

In recent years, co-design methodologies and the use of immersive virtual reality (IVR) have emerged as innovative tools for engaging citizens and stakeholders in the participatory design processes [3]. By allowing users to visualize and interact with design scenarios in virtual environments, IVR offers new opportunities for collaborative urban design. Despite these advancements, there remains a lack of empirical research on the effectiveness of IVR in co-design, particularly when two or more users are immersed in the same virtual environment while sharing the same physical space (co-located).

This paper explores the potential of co-located IVR as a tool for UPS co-design, focusing on a case study of Eindhoven’s train station square regeneration. By examining how IVR facilitates collaboration between participants (in terms of design discussion and decisions), this study aims to contribute to the growing body of research on the participatory co-design of UPS through IVR.

To investigate the effectiveness of the co-located IVR experience for the co-design of UPS, first, a literature review is performed as presented in the section below. The third section presents the method and materials used in this study, where the case study for UPS co-design is explained together with the co-design workshop task, its set-up and procedure, and the data collection and analysis methods. Next, the fourth section presents the data and results. The final section presents the conclusions of the study with the discussion of the outcomes, limitations, and recommendations.

2. Literature Review

This section gives an overview of the urban public space attributes, as well as the methods of co-design and IVR for urban design practices. It concludes with the gaps in the literature within the context of this study.

2.1. Urban Public Space Attributes

In this sub-section, we explain the reasoning behind the selected attributes of UPS co-design and their potential advantages and disadvantages for the environment, society, and economy.

2.1.1. Trees

The presence of greenery in urban public spaces is vital due to its many benefits to the environment and people. Firstly, green spaces offer aesthetic benefits, providing beauty and a refreshing change in urban settings [2,4]. Trees increase the willingness to linger, sit, or shop, promoting leisure activities by providing shade [4] and enhancing the city’s image [2]. They also regulate water [4]. Moreover, urban heat islands are mitigated by green amenities that cool the city [5,6]. By reducing temperatures, providing shade, and absorbing harmful pollutants during photosynthesis, trees help decrease ground-level ozone formation, improving air quality [5]. However, green spaces require high maintenance to sustain their positive impact. Poorly maintained greenery can negatively affect perceived safety [7]. Additionally, if not maintained, tree roots can damage infrastructure, making maintenance costly compared to simpler concrete pavements [7].

2.1.2. Benches

Benches serve multiple purposes, including sitting, watching, reading, and parenting [8]. They promote social interaction, provide comfort and resting spots, offer vantage points for observing scenes, and help with orientation [9,10]. Properly placed seating enhances active engagement and sociability, encouraging small conversations and interactions with others and the environment [11,12,13]. Comfortable seating is crucial for public spaces, as people seek spots also for passive engagement, such as observing activities around them without direct involvement [12]. For instance, seating arrangements around playgrounds or sports events facilitate passive engagement [13]. Proper placement also aids in directing people along pathways [14]. However, improper seating placement can cause issues. It can disrupt pedestrian flow, create bottlenecks, or obstruct visibility, leading to safety concerns [11]. Poorly placed benches can create blind spots, compromising security and potentially encouraging loitering, which means lingering without a specific purpose, especially in hidden areas.

2.1.3. Shelters and Landmarks

Shelters provide shade and protection from unpleasant weather and also promote social interaction; therefore, they can enhance both physical and psychological forms of comfort, which is crucial in public spaces [12]. Shelters and landmarks such as fountains give a sense of direction and identity to a space, acting as reference points for navigation and helping individuals make decisions about where to go [15]. Familiar, visually dominant, and visible from a distance, landmarks help organize our memory of space and shape our mental maps by highlighting spatial relationships [15]. However, shelters and landmarks can attract attention and foot traffic, potentially compromising their positive contribution to the public space. Increased activity and noise around these structures can intrude on privacy.

2.1.4. Access to Car Parking

Urban public spaces, especially train station squares, need to be accessible by a variety of modes of transport. In such areas, there is often problems with car parking, such as space shortage. To increase the accessibility of train stations and also the public square, car parking becomes a significant attribute. Parking, however, comes with some negative aspects. Parking takes up a large amount of land; this, in turn, lowers walkability and aesthetics. Increasing the number of off-street parking spaces near buildings pushes buildings apart from each other and increases the distance between buildings, making walking distances longer and decreasing the overall walkability. Curb parking could also disrupt walking paths [16]. Aesthetically speaking, parking is seen as having a negative impact on the surrounding area. Curb parking, for example, can disrupt building facades, while off-street parking lots can be bland [16]. Replacing vegetation and soil with pavement for parking purposes has an impact on the direct environment, leading to an increase in temperatures in the area [17].

Overall, car parking has a competing relationship with the three other selected attributes of trees, seating, and shelter. This arises mainly from the space allocation within a restricted area. Car parking takes up a large amount of space; thus, the choice is between car infrastructure and attributes that make the public space more enjoyable. The other three attributes of trees, seating, and shelter all have a complementary relationship with each other. Integrating green and seating arrangements amplifies the appeal of public areas. Trees also offer a natural backdrop and physical comfort to seating locations due to shade and shelter. Physical comfort is also the reason shelter and seating have a complementary relationship. Trees can provide a natural form of shelter and shade, therefore complementing the shelter attribute.

2.2. Co-Design and Immersive Virtual Reality

Solving the complex challenges that our cities face requires collaborative approaches that involve various stakeholders and the general public. As a result, citizen participation in urban planning and design emerged in the 1960s as a critique to conventional top–down procedures. Since then, new participatory, collaborative, communicative, and embodied methodologies have been incorporated into planning and design practices [18]. In participatory urban design, co-design workshops are commonly organized to encourage the active involvement of citizens and other stakeholders for design projects. These workshops aim to enhance collaboration, allowing participants to gain a mutual understanding of the challenges and opportunities within the project area [19,20]. To support the collaboration, enable participation, and promote interaction between non-experts and experts, digital technologies such as planning support systems, digital twins, virtual reality, dedicated apps, and location-based games have been introduced to the planning procedures [21,22,23,24]. In contrast to the traditional methods such as paper maps, 2D sketches, and 3D sketches, digital technologies aim to visualize the potential project scenarios and their outcomes with citizens and other stakeholders in a more engaging way.

Technological advancements have significantly improved the functionality and accessibility of immersive technologies, now collectively known as eXtended Reality (XR), which includes augmented, virtual, and mixed reality [3]. As virtual reality (VR) technology has advanced, its use for urban design and planning has expanded, offering more interactive, experiential, and immersive methods for designing and visualizing urban spaces, i.e., [25,26,27,28,29]. VR transports users to a computer-generated environment, providing the experience of “being in another place (virtual environment/world)” [30,31]. The immersive capabilities and interactivity of VR applications allow users to design, explore, and compare different design scenarios while also aiming to foster discussions and consensus in early design stages [32]. Moreover, with its collaborative capabilities, users can be co-located in the same virtual environment and can experience and shape it, either in the same physical location or remotely through online communications [33]. While co-located IVR presents promising opportunities for participatory urban design, it is important to acknowledge its inherent limitations. These include possible biases in how digital environments represent physical spaces, novelty effects, and accessibility concerns for participants with lower technology literacy [3]. Furthermore, the immersive nature of IVR may inadvertently exclude participants who are uncomfortable with head-mounted displays [25]. Such limitations of co-located IVR have been discussed in the literature of human–computer interaction studies [34,35]; however, applications of co-located IVR and its limitations are still scarce in the built environment-related studies.

In the current literature [25,36,37], VR technology and its use for co-design have started to be investigated. In these experiments, usually one person is immersed while others (designers) are involved through screen-casting. However, these studies do not test the effectiveness of a co-located IVR experience in which two or more persons are immersed for the co-design task of urban public spaces. Another issue with these new IVR-based studies is that they do not usually take into account users’ design competences (design experts vs. non experts), familiarity with technology, and their knowledge of the local context, which are crucial to create better participatory co-design experiences [25].

2.3. Problem Statement

Urban public spaces are important in the enhancement of citizens’ well-being by promoting physical activity and social interaction, especially given the ongoing trend of urbanization. Especially in urban plazas, several design elements, such as amount and organization of trees, landmarks, and presence of benches, can contribute to end-users’ overall well-being. The participation of citizens in the design process through co-design workshops with expert stakeholders ensures that these public spaces meet end-users’ diverse needs and contribute to their overall well-being [38], while also taking into account the public space management issues, such as maintenance and costs.

The lack of participatory roles for end-users and stakeholders in conventional practices leads to gaps in the design of urban areas. To bridge this divide, the development of methodologies and tools facilitating collaboration from an early phase between non-experts and experts becomes imperative [39]. However, the empirical research is still scarce on how these digital tools and methods can support certain stages of participatory urban design and whether they are appropriate for the task at hand, especially bringing together experts and non-experts [22]. As a new approach, co-design in an immersive VR, as explained in Section 2.2, might give the users (both experts and non-experts) access to a platform to voice their opinion in an early design stage. However, most existing IVR-based co-design studies have focused on single-user or remote collaboration scenarios, while the co-located experience of users (both within a shared IVR environment and in the same physical environment) has been missing. In this paper, we test the effectiveness of this approach for co-design through an experiment that focuses on the redesign of Eindhoven’s train station public square into a healthy public square as a case study.

3. Materials and Methods

In this study, we test how an IVR application can be used to have meaningful co-design processes for co-located users in terms of active design generation and collaboration in a public space design. For this purpose, we used a collaborative spatial design application, namely Arkio [40], which can be used in Meta Quest VR headsets and enables users to collaboratively create, navigate, and review spatial environments, such as building interiors and virtual cityscapes. It supports co-locating multiple users in the same virtual environment, and it enables designing together so that users can see each other’s design decisions and discuss them.

For our study, Eindhoven station square was taken as a case study, around which a large regeneration project will take place to densify the city center. Currently, 200 inhabitants reside around this area, which will be transformed into a mixed-use environment for 15,000 inhabitants [41]. The redevelopment plans can be seen in Figure 1. With the increasing number of inhabitants, this area will face pressure and require enhancements to meet the needs of its users. Creating a healthy public space and enhancing the connectivity between the city center and the broader urban scope are both central to these considerations, aligning with the core objectives of the ongoing project.

The approach of the IVR experiment included the following: an introductory presentation of the project aim, site conditions, design attributes and their implications, the IVR environment, and Arkio and its functionalities; co-design workshop sessions facilitating the design of the station public square by potential end-users in IVR, while the design conversations were audio recorded; and a survey regarding the IVR experiment. After the experiments were finalized, the survey data and the transcribed audio recordings were analyzed. A total of 20 participants, recruited through social networks, attended the experiment in November 2023. Each co-design workshop session included two participants; therefore, in total, 10 sessions were conducted.

In this section, we firstly describe the co-design task and its set up. Following that, we explain the procedure of co-design sessions. Finally, we describe the data collection and analysis methods, including the audio recording of co-located participants during the co-design task, observations on the design approaches, and decisions of participants, and the survey conducted after the co-design task was accomplished.

3.1. Co-Design Task and Set-Up

For this study, an immersive VR (IVR) experiment setup was prepared to facilitate design and collaboration. The 3D model of the urban public space was prepared in SketchUp and then transferred into the Arkio application. Attributes of urban public space for the intervention included trees, a car parking area, benches, shelter, and a fountain, based on our earlier study findings [1,25] and also the literature discussed in Section 2.1. The experiment aimed to enable a meaningful design and collaboration session, where participants were asked to collaboratively decide on the location and amount of these attributes, considering their advantages (i.e., stimulating healthy life), disadvantages (i.e., maintenance costs), and trade-offs, to design a healthy public space for future inhabitants and visitors that is also connected to the city center. Participants were encouraged to propose alterations and refinements that would make the proposed new plan acceptable to them based on perspectives assigned at the start of the session.

Each co-design workshop session included two participants who were randomly assigned to the same workshop session based on their availability. In each workshop, one participant was asked to consider his/her design decisions more from the local authority perspective, while the other participant was asked to emphasize end-user/citizen perspective. These perspectives/roles were assigned to each participant based on their preference. If the participants did not have a preference, then they were assigned to their role by the researcher. While the goal remained consistent for both parties, “creating a healthy public space and aligning with the core objectives of the redevelopment on connectivity”, this way, we aimed to stimulate discussions and discourse on the design decisions and outcomes in a more realistic way. Therefore, it was important for participants to have an understanding of the dynamics between attributes for designing the given public space within the virtual environment during the workshop. Due to this, an explanation of the advantages and disadvantages of these attributes and their relations was provided to the participants at the beginning of the co-design workshop sessions. We conducted 10 workshop sessions with a total of 20 participants. Although this number is reasonable given the exploratory nature of our study, it is important to acknowledge that the small sample size limits the representativeness of different population groups. Additionally, participants’ prior experience with VR, co-design, and participatory processes may have influenced how they engaged with the virtual environment and the co-design task. To account for this, we also collected information on participants’ prior experience in these areas, as well as their age, gender, living environment, and whether they had studied a built environment-related field.

As can be seen in Figure 2a, Arkio has many functionalities. For the ease of use, we stacked the attributes in the virtual environment, near the virtual case area (see red rectangle area in Figure 3b), instead of making the participants go to the attribute library and choose an attribute. This way, participants needed only “move” (moves attributes within the virtual environment) and “delete” (deletes attributes from the virtual environment) functions. With these two functions, participants could move, locate, and delete the provided attributes within the design area in the virtual environment. The use of attributes was optional, and it was not mandatory to apply all attributes during the design. Another important function to learn for participants was how to navigate and teleport within the virtual environment. This was possible by using the controller and controller buttons of the VR headsets. Additionally, it was important for participants to learn about the different perspectives in the virtual environment. The first is the “Model” perspective, which provided a zoomed-out view of the model. This perspective allowed participants to move attributes more easily and make broad adjustments. The second was the “Immersive” perspective, where participants entered the model in a first-person view at a 1:1 scale. This perspective enabled them to experience the design firsthand and assess its spatial and visual impact from a human-scale viewpoint.

In each co-design workshop session, two participants, who were physically in the same room, were co-located in the IVR environment via a VR headset, namely Meta Quest 2, and were asked to design the given area within 30 min. Each session was facilitated by a researcher. A connection was established between the Arkio system and the researcher’s computer. Thus, the researcher could follow and take notes of the user interactions within the virtual environment through the computer screen and could assist the users when needed. Figure 4 shows an illustration of the co-design workshop setup. To adhere to the spatial requirements outlined by Atkinson (2022) [43], in accordance with established guidelines, a minimum spatial allocation of 2 × 2 m per participant (equivalent to 4 square meters) was provided.

3.2. Procedure of a Co-Design Workshop Session

Each session started with a presentation, elucidating the workshop’s purpose and the broader research context. Firstly, the co-design methodology and the underlying concept of using IVR were explained, including the overarching research objectives. Subsequently, the presentation transitioned to the explanation of the Arkio tool, its user interface, and its functionalities. In total, this presentation had a timeframe of 10–15 min.

Following the introductory presentation, a trial session was designed to familiarize the participants with the use of VR headsets, controllers, and the Arkio app. This phase included the exploration of fundamental Arkio functions, such as moving and deleting objects, and user navigation within the virtual environment. For this purpose, a designated test virtual environment was provided. During the trial phase, participants were immersed in pairs, and the exploratory IVR experience was conducted within a maximum timeframe of 15–30 min.

Subsequently, a break was provided to the participants in order to mitigate any potential VR sickness after the trial. After this break, a second presentation was administered. This presentation elucidated the research area of Eindhoven station plaza and introduced the different attributes that participants could use to design the area and the positive and negative effects of these attributes on the environment, as described in Section 2.1. The presentation concluded with a scenario (goal of the co-design session as designing a healthy public space that is connected to the city center), featuring different participant perspectives, with one participant having more of an end-user perspective and the other having more of a municipal perspective. The duration of this second presentation, including the break, was approximately 20 min. This allowed participants to have some rest before the second IVR session.

After that, participants were immersed within the virtual environment of the pre-defined area of Eindhoven station square through VR headsets. Throughout this phase, conversational interactions and visual focal points were captured via recording devices and through the observations of the researcher. This session duration was up to a total of approximately 30 min. During this time, participants were able to take breaks, take seated positions, or discontinue their participation at their discretion.

Upon completion of the co-design session, participants were directed to complete a survey. This survey aimed at understanding participants’ background and their experience with collaborative design in the co-located co-design IVR session and the method provided. This survey took around 10–15 min to complete. Finally, the researchers engaged participants in a collective discussion to reflect upon their workshop experiences and delve into design decisions. The overall duration of one co-design workshop was set within a time frame not exceeding 120 min.

3.3. Data Collection and Analysis Methods

For data collection, we used a multi-method approach that enabled us to triangulate the surveys, audio recordings, protocol analysis, and behavioral observations at an aggregate level to validate participant responses. In this sub-section, the method for participant audio recordings and protocol analysis is first explained. Later, the method for observing participants’ design approaches and decisions is elaborated upon. Finally, the survey questions are described.

3.3.1. Participant Audio Recordings and Protocol Analysis

During each co-located co-design session, we recorded participants’ verbal communications through audio recording. This data collection was aimed at understanding how the verbal communication of a team engaged in a shared task occurs within the co-located IVR environment and which subjects were important for them to discuss. This way, we could understand whether the communication was mostly about design or the tool and whether the provided methodology for co-located co-design can support users to have meaningful design discussions. For this purpose, we adopted protocol analysis as the method for analyzing the audio recordings. Protocol analysis is a commonly used approach in collaborative design research and is used to understand thought processes of participants when they are “thinking out loud” to solve design problems [44,45,46].

In the context of protocol analysis, a crucial element is segmentation, referring to the procedure of partitioning spoken text into discrete segments [46].

Table 1. Coding for communication used in protocol analysis.

	Communication	Code	Description
Communication control	Communication Control		Flow of Conversation
	Interruption by a participant	IBP	When a design participant interrupts another participant.
	Interruption by an instrument	IBI	When a design participant is interrupted by instrument functioning, e.g., wrong button, instrument shutdown.
	Handing over the conversation	HOC	Handing over the conversation from a design participant to another participant, possibly through questions or by specifically naming the other participant, e.g., “You know?”.
	Pause	PAU	Pausing during the communication.
Conversation Topic	Design communication		Design related interaction
	Scenario-related communication	SRC	When design participants talk about scenario-related things.
	Social communication		Social interaction
	Non-scenario-related social communication	NSRSC	When design participants talk about non-scenario-related things.
	Communication technology		Tool related interaction
	VR instrument	VI	When design participants discuss the use of tools for design in the IVR environment.
	Examining	EXA	When a design participant examines what can be done by using the instrument.

employs coding inspired by Chowdhury’s (2020) [44] research, which shares a similar investigative scope. Four primary communication aspects were identified. The first pertained to communication control, wherein the monitoring of conversational flow was undertaken. This included instances of tool-induced interruptions, interruptions from other design team members, or conversational shifts driven by questions. The second category encompassed design communication, including discussions concerning design-related tasks within the given scenario, such as ideas or the positioning of an attribute within the environment. The third category, social communication, captured exchanges unrelated to scenario and design-related matters. Lastly, the communication technology category captured dialogues related to tool usage, encompassing discussions regarding the instrument’s utility or actions performed using the tool.

3.3.2. Observations on the Design Approaches and Decisions of Participants

During each co-design session, the researcher recorded the design process of participants in the IVR. Moreover, the researcher followed the behavior of the participants both in the real world and in the virtual world and took notes. In this way, we aimed to understand the design approach and decisions of the participants, such as which attributes they selected first, whether one of the participants took the lead, or if both participants contributed to the design implementation equally through the functions of Arkio.

3.3.3. Survey

After the co-design session, a survey was handed to participants. The first part of the survey included questions related to participants’ background and socio-demographics such as age, education, and living environment. The second part of the survey comprised questions related to participants’ previous encounters with the tools and methodologies employed during the workshop. This part of the survey assessed participants’ familiarity with co-design and VR technology and their involvement in urban (re)development initiatives. Prior experience with VR, co-design, or participation in such contexts can imply an influence on the design process and its outcomes. This could impact aspects like user comfort, efficiency, creativity, and the adept utilization of VR tools and functionalities. The third part of the survey was about assessing the participants’ learning experience during the workshop. It included questions related to participants’ comprehension of the workshop’s objectives and attributes. Additionally, there was a question regarding satisfaction with the overall duration of the workshop.

The fourth part of the questionnaire was about evaluating the usability of the VR tool within the framework of co-design. This section sought to ascertain (i) whether the utilization of the VR tool enhances the overall user experience or promotes a sense of safety (if the participants feel safe within the IVE), to identify potential drawbacks, and (ii) to gather opinions on the perceived ease of use of the VR tool. The fifth part of the questionnaire was related to the communication experience of participants during the co-located co-design session. The questions focused on understanding the quality of communication among participants in the IVR setup, assessing the interactions between participants and the researcher, and exploring the advantages and disadvantages associated with co-location (group immersion) in the IVR set-up. The final part of the survey had questions related to participants’ willingness towards future utilization of the VR tool for urban design and planning. Specifically, it focused on understanding participants’ preferences for employing this tool and co-location in public co-design assignments within the context of urban development, relative to more conventional methodologies and tools such as surveys, face-to-face meetings, and public hearings. Additionally, this section collected feedback about the experimental process itself. The data collected through this survey were analyzed in a descriptive way.

4. Results

In this section, first, the communication throughout the workshops is analyzed through protocol analysis. Following that, the design approach of the participants is examined, and then the survey responses are investigated. The results are derived from the 10 co-design workshops involving a total of 20 participants. Given that there was no minimum required time, participants had the flexibility to conclude the activity at their discretion. This arrangement was implemented to avoid a potential of VR sickness. A session would only stop once both participants confirmed they had completed the design. It is noteworthy that no workshop concluded prematurely due to VR sickness; rather, the conclusion was determined by participants’ confidence in their final designs. Consequently, this caused a variety in the duration of workshops ranging from 18 to 31 min.

4.1. Protocol Analysis

The protocol analysis investigated two points of communication, which are communication control and conversation topics (as was described in Table 1). Communication control pertains to the overall flow of conversation, trying to answer questions such as how are participants moving the conversation forward? Are participants interrupted by others or the instrument? Is there any pause in the conversation? Conversation topics aimed to answer what participants are talking about during the workshop. This is categorized into three sections: design, social, and tool communication.

Table 2. Count of communication events and topics happening in each session.

Communication	Code	S1	S2	S3	S4	S5	S6	S7	S8	S9	S10
Duration (minutes)		28	28	30	28	30	20	18	29	30	31
	Counts
Communication control
Interruption by participant	IBP	4	4	6	1	1	1	3	3	1	2
Interruption by instrument	IBI	15	5	17	6	2	5	5	6	4	5
Handing over the conversation	HOC	20	13	13	21	7	18	12	14	14	20
Pause	PAU	0	7	1	5	8	0	2	2	3	0
Design communication
Scenario-related communication	SRC	49	41	47	32	33	39	36	40	38	36
Social communication
Non-scenario-related social communication	NSRSC	0	1	0	2	1	0	3	1	0	0
Communication technology
VR instrument	VI	26	12	17	12	12	11	12	11	10	16
Examining	EXA	29	24	25	11	10	16	16	21	18	19

shows the overall counted events (raw counts) that happened in the workshop sessions. Session durations varied (18–31 min), which could potentially affect communication and design outputs. To account for this, in the text, we report proportional measures in communication analysis rather than raw counts, reducing potential duration-related bias.

4.1.1. Communication Control

Interruptions by a participant (IBP) and instrument (IBI) were not common, except for two sessions out of ten. Participants were usually talking calmly and letting each other finish sentences. Interruptions caused by the instrument occurred due to accidental movement of attributes, changes in the size of attributes, entering of the virtual environment, and model deletion. Overall, the communication felt natural, and people used questions, names, etc., regularly to hand over the conversation (HOC). A pause in conversation (PAU) was unusual, so there was a continuous communication during the workshop sessions. Notably, workshop session five had the largest total pause in conversation with 6 out of 30 min being a pause. Even in this case, there was an ongoing conversation for 24 out of 30 min. Moreover, a pause in conversation was not always detrimental to communication; pauses usually occurred due to activity within the virtual environment, such as moving attributes to their desired location.

4.1.2. Conversation Topics

The predominant focus of the workshop’s discourse revolved around the scenario (SRC). Participants expressed design ideas; some examples are preferences for an open area near the station and a desire to place parking close to the established road. Conversations on context included questions such as the location of the city center or the sunlight distribution on the public square. Dialogue also covered the given different attributes and the missing (not given) attributes, the purpose of attributes, and revisiting positive and negative aspects associated with the given attributes. Overall, SRC was the most common topic throughout all workshops. It is interesting to note that, in sessions 6 and 7 where session duration was relatively less than others, SRC took place proportionally more than other sessions.

Examining (EXA) was the second-most discussed topic. Two different design methodologies were frequently conducted. These are (i) tackling the design completely together, either attribute or area-related, or (ii) individual design choices and reviewing these together afterward. Even when duos did not design the complete square together step by step, examining still occurred regularly. This indicated that collaborative efforts were prevalent during the square’s design. Participants expressed enjoyment in exchanging ideas with each other, which could explain why the SRC and EXA were the most common conversation topics.

Conversation on tool use (VI) occurred throughout the workshop, and typically, the focus on immersion came before any other topic. Examples included discussions about their immersion in the model, recognizing connections between the model and the real environment, and observing the other participant’s simultaneous immersion. Over time, discourse on the tool shifted to a more question-oriented discussion. These questions revolved around assisting with forgotten functions, such as navigation in the model (e.g., how do I enter the IVE again?), operations (e.g., how do I rotate the parking lot again?), and directions (e.g., I think I am lost, can you help me?). Additionally, there were questions on functionality inquiry, such as if it was possible to change the paths of the park, copy–paste elements, group elements, and create more attributes. Despite the recurrence of these questions, such discussions were typically brief.

As for non-scenario-related social communication (NSRSC), it was non-existent within the workshops, usually not more than one sentence if it occurred at all. Small jokes or real-life experiences from the area occurred; however, these interactions were limited to just one sentence.

4.2. Design Approach Within the Workshop

In this paper, our aim was to explore and understand the effectiveness of co-located IVR experience for meaningful collaboration between participants in terms of their design discussions and decisions. Therefore, even though the final design is not the primary focus of this paper, examining recurring design decisions could give insights on understanding the co-located IVR experience. Therefore, in this section, the design decisions during the sessions were considered in a more general sense. Participants had only 30 min to design an entire public square, which is not enough time to create a final detailed design, including the exact location of attributes. It is more important to capture general design preferences and understand why participants made these design choices. An example of design output can be seen in Figure 5.

Table 3. Reoccurring design decisions and the reasons behind the choices.

Design Choice	Why
The parking lot is located close to the main road	Easy access to parking Leaving more room on the square for other functions Ability to hide parking from the rest of the square
The fountain forms a centerpiece of their surroundings, including bench placement around the fountain	Counteract the parking Focal point of the design Chill area
Shelter placed close to the parking lot	People can be dry while waiting to get picked up Payment point for parking
Low number of trees close to the station	Give a better orientation of the surroundings for people entering the city from the station
Benches chosen based on their location (e.g., wooden benches more inside the park, aluminum benches close to the station)	Divide the overall space into functional zones

illustrates the recurring preferences regarding the given attributes, as attendees during the square design process indicated the reasons behind their choices. In all designs, the fountain was incorporated. Users showed a preference for a high number of trees, with the minimum number of trees in a design being 13. Moreover, users expressed a preference for many benches. Finally, the parking lot was located near the main road, and the shelter was placed near the parking lot.

Although the final designs of each duo differentiated from each other, remarkably, each duo tackled the attributes in a consistent order. Initially, parking was tackled, followed by the placement of the fountain. Subsequently, the area was designed with trees, benches, and a shelter. Participants stated that they started with the parking lot due to the size of the attribute, dominating the overall design of the square. The fountain followed, emphasizing the center point of the square and countering the dull parking location. After this, participants usually designed the square either based on location (e.g., left to right) or based on attributes (e.g., trees followed by benches and finally shelter).

Collaboration on the design task occurred throughout all sessions, as evidenced by the high occurrence of SRC and VI. It is important to note that even if a participant had less of a grip on the Arkio tool, they actively participated to the best of their ability by providing design ideas and feedback and by joining in on the discussion and decisions. Typically, in each session, the participant with a better understanding of the tool played a more active role in designing, placing the attributes, and assisting their partner. This highlights that a collaborative immersive experience enhanced the overall workshop experience.

Regarding the working environment, the majority of participants opted to remain seated throughout the co-design session, with only two exceptions. One participant began the session standing but transitioned to a seated position after 18 min, ultimately completing the session while seated. Conversely, another participant initially sat but stood up after 15 min, concluding the session in a standing position.

4.3. Survey Findings

After the design scenario concluded, participants completed a survey. This section explores the overall survey responses and is divided into the following topics: personal background, prior experience, confidence in the final design, learning experience during the workshop, VR as a tool for co-design, communication and teamwork, and finally, the future use of VR in co-design for urban (re)development projects. Per question, participants were asked to elaborate on their answer for the question. For instance, if the question was, “How confident are you with your final design?” and the participant responded with high confidence, the subsequent follow-up question would be, “Could you describe why you have high confidence in your final design?” This format was selected to understand the reasons behind the responses.

As shown in

Table 4. Summary of participant characteristics.

Variable		Number of Participants
Age (mean)		25
Gender	Male	15
	Female	5
Living environment	0–100,000 inhabitants—Rural areas, small town/city	4
	100,000+ inhabitants—Large city	16
Built Environment related study	Yes	5
	No	15
Familiarity with VR	Yes	7
	No	13
Familiarity with co-design	Yes	5
	No	15
Familiarity with participation	Yes	3
	No	17

, our sample consisted of young adults whose age ranged between 21 and 29 years, mostly males, living in a large Dutch city, and most did not have a design- or built environment-related study background. The majority of participants lacked familiarity with co-design, VR, and participation in urban design projects. Notably, none of the participants responded with yes to all three aspects, making the combination of three aspects in the experiment a novel experience for the participants. Those acquainted with co-design primarily had a study background in built environment-related studies. Previous VR experiences varied, ranging from gaming to involvement in other VR-related research studies. Remarkably, only three attendees had prior experience in public participation for an urban (re)development project.

Table 5. Descriptive statistics of the survey.

Theme	N	1 (Very Low)	2 (Low)	3 (Somewhat Low)	4 (Neutral)	5 (Somewhat High)	6 (High)	7 (Very High)
Confidence in Final Design	20	0	0	1	6	8	4	1
Clarity of Attributes	20	0	1	1	0	2	11	5
Role-Playing Experience	20	0	1	0	4	0	12	3
Goal and Task Clarity	20	0	0	0	2	3	7	8
Satisfaction with Time Allocation for Tool Exploration	20	0	1	0	2	8	9	0
Satisfaction with Time Allocation for Design Scenario	20	0	0	1	5	8	6	0
VE and VR Usability	20	0	0	1	2	9	6	2
VR Impact on Design Experience	20	1	0	1	0	0	9	9
Communication and Teamwork with Group Member	20	0	0	0	0	1	15	4
Communication and Teamwork with Researcher	20	0	0	0	1	1	11	7
Shared VR Experience	20	0	0	0	2	3	10	5
Likelihood to use VR for Participatory Co-design Again	20	2	2	0	1	6	5	4

provides a descriptive summary of the survey results. Participants were asked about their confidence in the design. Seven participants rated their confidence as neutral or lower. While all participants were satisfied with their final design, they were unsure if it met “good” design standards for urban design.

Participants were also asked about their experiences during the co-design sessions, and questions were related to attributes, roles, goals, and time allocation for exploring and designing. According to most of the participants, attributes within the model were adequately explained during the workshops. Participants reacted positively to the presentation of attributes beforehand, expressing that this discussion helped with their decision-making during the design. Participants were also asked about attributes that were missing during the workshop that could improve the public space design. Trash cans, streetlights, bushes, tables, and the possibility of changing the walking paths were mentioned.

Most participants had a positive experience with the allocated roles of the resident and the representative of the municipality, although some improvements were suggested. Especially, some participants noted challenges with taking the role of a municipality representative as understanding the government’s preferences, especially with the absence of a defined budget. On a positive note, participants mentioned that different roles, in this case, the municipality vs. the users, helped enhance immersion during the design.

Participants provided positive feedback regarding the clarity of the goal and task. The overall task, which was to design a public space in Eindhoven as a duo, was clear and easily understandable. Participants appreciated the explanations about the case study before they started their design, along with a sufficient explanation of what to expect during the session.

Participants were satisfied with the time allocated (around 15–20 min) to explore Arkio before their design task started. However, some participants expressed a preference for a more detailed explanation of the VR tool and application and why it was chosen over other methods.

Similarly, most of the participants were satisfied with the time allocation (up to 30 min) for the main task of designing. A crucial factor of choosing a 30 min limit was the possible VR fatigue. Nine out of twenty participants mentioned experiencing some form of fatigue, ranging from tired eyes and dizziness to headaches. However, during the design task, the discomfort did not reach a level where participants took a break or had to stop the overall workshop. Despite these challenges, the majority of participants described the VR tool and application as easy to use.

It is noteworthy that most participants stated that the VR tool enhanced their design experience, especially via enabling multiple viewpoints during design. Multiple participants highlighted that the interactive design process assisted them in decision-making. Participants with lower ratings indicated that they liked the workshop overall but did not feel the VR tool enabled them to acquire new skills for urban design.

Communication among group members was mostly perceived as positive. The interactions were characterized as fast, simple, and direct, enabling participants to understand each other’s ideas. They enjoyed sharing design decisions, and even when splitting their work, nothing was considered “permanent” until discussed collectively. This approach facilitated multiple perspectives on the design, a factor that attendees found to be positive. Communication between the participants and researcher was considered mostly positive and, by some, even mandatory.

According to participants, a collaborative co-located immersive experience improved the overall effectiveness of the workshop. The task of designing a public space became less daunting when approached collectively. Participants could assist each other, validate design choices, and engage in discussions on design decisions, leading to alterations.

Fifteen participants expressed their likelihood to engage in co-design with VR again if the municipality organized a workshop. Notably, participants showed interest in participating only within their immediate living environment (neighborhood). Participants were excited about using a more modern tool and having the opportunity to express design ideas as a non-expert. Conversely, less enthusiastic participants cited concerns about the potential time commitment, a general lack of interest in urban design, or feeling ill-suited for the tool.

5. Conclusions and Discussions

In this final section, we discuss the main findings, limitations, and recommendations for future research.

5.1. Discussions

Enhancing UPS is crucial to support the well-being of their users. These spaces directly and indirectly impact individuals’ well-being by encouraging physical and social activity, outdoor recreation, and stress reduction. Healthy UPS should incorporate qualities such as urban greenery, safety, and support for social environments. In this study, we explored the effectiveness of co-located IVR for participatory co-design of UPS, using Eindhoven Station Square as a case study

For this study, 10 IVR-based workshop sessions, involving 20 participants in pairs, were conducted. Participants were asked to collaboratively design the given UPS into a healthy public space within 30 min by deciding on the location and amount of the given attributes, considering their advantages (i.e., stimulating a healthy life), disadvantages (i.e., maintenance costs), and trade-offs. In each session, one participant was asked to consider his/her design decisions more from the local authority viewpoint, while the other participant was asked to emphasize end-user viewpoint. Each session was facilitated by a researcher.

Our findings show that even participants with limited experience in IVR, co-design, or urban design/planning were able to actively engage in the co-design process. Participants thought the design attributes and their implications were clear to them, showing that the pre-discussion of design attributes was helpful in shaping their decisions. Throughout the design process, participants thought of other relevant attributes, such as light poles, trash cans, etc. Yet, participants suggested that the model could be improved by incorporating additional attributes and realism, which can also improve the presence in IVR [47]. However, there is still discussion in the literature on whether increasing realism affects users’ experience and behavior in IVR [48]. Moreover, they considered the given IVR design tool (adapted with minimum functionalities and conveniently placed attributes) suitable and easy-to-use for the task at hand. The immersive, co-located setup enabled a focused and task-oriented co-design process. These findings suggest that such tools should be designed in a more intuitive way for the task at hand to facilitate meaningful participation [25].

Our findings showed nuances in collaborative dynamics. While participants generally contributed equally to the design process, those with a better grip of the tool tended to take the design actions but always in consultation with the other participant. This dynamic highlights the role of digital fluency in shaping collaboration. Participants with a higher confidence in using the tool tended to take on more operational control during the design process, which could unintentionally create power asymmetries. While most interactions remained collaborative, it underscores the importance of balancing tool usability with facilitation strategies that ensure equitable participation. In real-world applications, such dynamics should be monitored closely to avoid marginalizing less digitally confident participants.

The results show that co-located IVR had a positive influence on participants’ engagement and collaboration. Participants were confident with their final designs, attributing this confidence to the possibility of discussing and confirming the design decisions with the other person. Additionally, the design approaches and most of the design decisions were reasonable. Overall, most of the participants would like to participate in a future co-design process that make use of IVR. While we observed engagement and collaboration during co-design sessions, we recognize that isolating the specific influence of IVR from other contributing factors, such as group dynamics, participant roles, and prior experience, is inherently challenging. Most participants had limited experience with VR, suggesting that their engagement was not solely driven by technological familiarity. Still, further studies should explore these variables more systematically.

In terms of communication, protocol analysis confirmed that participants’ communication mostly revolved around design generation, with minimal social communication. Participants used questions to steer the conversation on both the design generation process and decision-making. As for non-design-related communication, this was notably scarce. Communication revolving around the use and capabilities of the tool was most common during the start of the workshop and gradually faded through time. In previous studies by Chowdhury [44,49], social communication was a more prominent topic. However, in these studies, the collaboration between two participants occurred in different modes, with one participant designing on a computer screen and the other in an IVR environment, and therefore, the effect of a co-located IVR environment was not explored. In our study, the minimal level of social or informal communication may be attributed to the co-located immersive and interactive nature of the IVR environment, along with the time constraint of the co-design session (within 30 min), which seemed to encourage task focus and engagement. While participants shared the same physical space, their attention was largely directed towards the virtual setting. Unlike traditional workshops, the absence of visual cues like eye contact and body language may have reduced opportunities for casual social interaction. While this focused communication may enhance design efficiency and clarity, it also suggests the following trade-off: the immersive format may suppress the kinds of informal dialogue that can enable interpersonal connection, creativity, and shared ownership. These reflections reinforce the need for future IVR co-design setups to consider not only technical usability but also the social and relational dynamics that immersive formats may alter.

5.2. Limitations

The model utilized in this research exhibited certain limitations, as identified by the participants. While the ability to modify the time of day was an available feature, some participants lacked the necessary expertise to perform this adjustment effectively. Additionally, multiple participants expressed an interest in exploring lamp post attributes to assess dynamic night lighting, highlighting the absence of dynamic features in the research model. This concern aligns with the existing literature emphasizing the importance of dynamic features in IVR for comprehending the consequences of design decisions [25,50]. Furthermore, participants found it challenging to envision the overall use of the square. A dynamic model incorporating animated pedestrians could be a crucial enhancement, as it would better illustrate pedestrian flow and usage patterns.

It is important to acknowledge that protocol data may not always be comprehensive, as participants may only verbalize a subset of their cognitions. Therefore, protocol analysis possesses inherent limitations, particularly in its capacity to capture non-verbal thought processes during the design process. Consequently, the realm of non-verbal communication often remains underexplored within this methodology.

Another point of attention is the participant recruitment process and participant grouping. For this study, we were able to recruit participants from close networks through emails, word of mouth, and messages. Since the researcher assigned group compositions without participant input, this predetermined arrangement could have potentially affected the collaborative dynamics. Future studies may consider a more varied recruitment approach to include participants from different backgrounds, age groups, and socio-economic groups. Moreover, group compositions can be determined based on a methodology that considers people’s backgrounds and personality type. Furthermore, our proposed method was tested only in one spatial setting (station square), whereas different communication behaviors might occur in other spatial settings (i.e., interior design, street design, and campus design).

Despite these limitations, the research methodology presented in this study demonstrated value in facilitating co-design discussions. However, the identified limitations highlight opportunities for refinement. Enhancing the model with intuitive time-of-day adjustments, dynamic pedestrian simulations, and additional lighting attributes could significantly improve its applicability. Additionally, refining the participant recruitment strategy is essential for future studies. By addressing these aspects, future research can create a more seamless and informative immersive design experience, further bridging the gap between expert and non-expert participants in urban planning.

5.3. Further Research Recommendations

Potential future research should reconsider the participant recruitment strategy. Our recruitment strategy relied on convenience sampling through researchers’ networks and assigned group composition. This limits generalizability, as participants may share similar demographic or technological profiles. Future studies should include more diverse samples and allow participant-driven group formation (i.e., based on personality, digital fluency, or collaboration type) to explore the impact of group dynamics on co-design.

Future research could also explore the IVR-based design method in terms of varying the degrees of participant design freedom. Currently, participants are only able to move attributes. Introducing a more choice-based approach, such as selecting from predefined attribute configurations (e.g., options for 10, 15, or 20 trees, or predetermined parking locations), may help participants feel less intimidated. However, reducing the level of flexibility could keep participants from more nuanced design decisions, such as a reduced number of trees near the station. Consequently, valuable insights from non-experts could be lost. Therefore, an important avenue for future research is to assess the impact of different levels of participant autonomy on the final design outcomes.

In terms of the overall methodology, one possible refinement involves dividing the process into multiple workshops. Conducting the first workshop in larger groups could facilitate multiple perspectives and encourage information-sharing among a broader audience. However, when designing in the virtual environment, smaller groups—preferably pairs—proved to be effective, as simultaneous immersion enabled meaningful discussions and diverse viewpoints. Further research should explore the optimal number of participants immersed at the same time, as this study only examined two participants per session. It is essential that an expert facilitator can effectively guide all immersed participants to maximize the method’s potential. Another methodological refinement is related to the protocol analysis, which was conducted by a single coder. We acknowledge that including multiple coders and assessing inter-rater reliability would enhance the objectivity of the qualitative findings and should be considered in future research.

Although our findings suggest that co-located IVR supports immersive and effective co-design experiences, the absence of a comparison group using conventional tools limits our ability to determine whether observed benefits were due to IVR specifically or general enthusiasm about novel technologies. Additionally, due to the exploratory nature of our research, we cannot ensure that the sequence of design decisions made by participants is not the result of external factors, such as initial workshop instructions or tool interface. Therefore, we suggest future studies to make comparative analyses with control groups that use a different co-design method to address potential novelty effects and other external factors, such as workshop instructions. Moreover, it is critical to address inclusivity and accessibility challenges in the development of IVR tools. Future research should explore user-centered adaptations of IVR environments that accommodate different levels of digital literacy and physical comfort, ensuring equitable participation across user groups.

To conclude, we can say that, with this approach, users can collaboratively generate designs while actively expressing their wishes and needs for future UPS. Both visual and verbal communication can enhance users’ confidence in their design decisions, allowing them to actively contribute to the design process and, therefore, bridge the gap between designers and non-experts. For future experiments, we recommend not extending IVR sessions beyond 30 min to prevent user fatigue. Additionally, communication between participants and the researcher is key; so, if the number of participants increases per session, the number of researchers might need to increase as well. Furthermore, it is important for the participants to build up knowledge and expertise with respect to the design area, goals, attributes, other participants, and the IVR environment. Therefore, when this approach is used in a real-life application, it is suggested to have several workshops touching on each stage. Finally, we recommend a follow-up study that focuses more on the design decisions (rather than the process of co-design) of an IVR-based co-design approach and to what extent these design decisions can be translated into real practice.