## 1 Introduction
to unravel the evolution of digital graphic designers' support during the survey (the pre-design) and design processes before rethinking these processes. The first digital drawings were created using computer-aided design (CAD) software and appeared in the 1980s. In the following decades, geographic information systems (GISs) increasingly offered new ways to capture data in the form of as-built plans. Three-dimensional modeling and animation software enabled a dynamic environment, and (infrastructure) building information modeling (BIM) was introduced for collaboration on 3D drawings. The addition of 3D city models laid the foundation for the development of digital twins. Animation opportunities for traffic simulations for different vehicle users and pedestrians (including accessibility for the disabled, changing weather, or seasonal conditions and noise) are now available [8]. Contrary to recent United Nations recommendations, the combination of virtual reality (VR = the experience in a completely virtual world) and augmented reality (AR = the combination of the physical world with an extra virtual representation), called mixed reality (MR), has not to our knowledge yet made its way into the public space design process [9]. Since the 1990s, a divide has emerged between public space designers and digitally inspired 3D spatial experts. Although new digital graphics tools such as extended reality (XR = the combination of VR, AR, and MR) can aid the design process, many public space designers are unfamiliar with them. Communication and participation should be part of the design process. Moreover, designing a public space should be a transdisciplinary process involving citizens rather than an interdisciplinary process of experts, as citizens use public spaces as the end-users [10]. Usually, only one-way communication takes place after the design phase; however, interactive communication during the design process is more desirable. Participation, i.e., the opportunity for citizen consultation, is preferred but not consistently applied. Co-creation or co-design goes beyond participation by motivating citizens to design in collaboration with other citizens and designers. Organizing co-creation or co-design tends to be the exception and is limited to experimentation. Similarly, communicators for public space projects mainly include the use of 2D drawings and sometimes a few 3D images. Nevertheless, 2D plans are more difficult to understand than 3D visualizations [11]. Three-dimensional visualizations are often collages that are created using image processing software. Animated video visualizations or (online) interactive 3D environments are rarely offered. Mostly, VR applications in participation are still limited to experiments [12]. The intelligibility of graphical documents is crucial, as more and more citizens are willing to participate in urban design processes. The growth of such interactions needs to be supported. With the help of technology, a future shift from a purely physical to a cyber-physical experience of public spaces is conceivable [13]. Since the emergence of digital 3D techniques in other design domains, there has been a shift in the design process to start in 3D, from which 2D cuts and views only emerge from the 3D designs at a later stage. This research analyzes why this is not yet standard in the public space design process and whether game-changing developments can be expected using XR or online 3D. We formulated our research questions as follows: \"What is the attraction and resistance of 3D and extended reality in the co-creative public space design process and how does this differ between professional designers and non-designer stakeholders?\"; and \"How is the use of these techniques in 3D co-creation and co-design practice appreciated?\". The remainder of the paper is organized as follows. Section 2 provides the literature review and Section 3 explains the method. Section 4 reports the results, which is followed by the discussion in Section 5 and the conclusion in Section 6.