## 1 Introduction  
Public spaces are the realms between private domains [1]. Regardless of age, ethnicity, or physical limitations, everyone uses physical public space in all functional and physical categories to move, rest, meet, engage in recreation, or play sports [2]. Various government agencies manage public space and are responsible for its design, realization, and maintenance. As part of the urban design discipline, public space design is a complex and slow process wherein the results determine the future use of the physical world. The nature of theories of urban design, which have their roots in the humanities but extend to empirical science, links the material aspects of urban space with the social aspects of urban life [3]. Looking back in history, public space designers were predominantly seen as technicians who were almost omnipotent in public space design, using pen and paper as designing and decision-making tools; in fact, many of them still use these tools. It is striking that most current public space design processes, which have been increasingly supported by digital techniques since the 1980s, are developed in a purely 2D environment,whereas 3D technology is a primary tool that is found in most consumer products' and architectural design processes. When citizens, the future users of the public space, are involved in participatory processes, a 3D co-design is not a standard tool. To better understand the use of digital graphics techniques, it is first necessary to decipher the design process of urban and public spaces. [PERSON] et al. (2009) describe the following phases [4]:  
* The survey (or pre-design phase) comprises the spatial analysis of the environment. * The design phase includes the evaluation of various design options, the decision making, and the building permit acquisition process. * The maintenance phase includes the realization, use, and aging process (until the start of a new design process). The design process begins in the survey phase, which comprises a detailed spatial analysis of the existing environment in primarily 2D graphic documents (Figure 1a). The subsurface, mobility aspects, hierarchy of roads, and traffic flows are decisive elements that constrain the design options; geodata and specific datasets provide aid when completing the entire urban design survey's spatial context. Usually, the spatial survey is limited to an objective collection of observable information about the environment. In this phase, the involvement of residents and future users is an exception. In the design phase, initial drafts present conceptual studies based on standard profiles for classic roads or specific spatial solutions for squares and parks. Many authors have developed design principles; however, the applications often depend on the designer's skills [5]. [PERSON] (2019) [6] highlights the gap between the general recognition of the minimum requirements for the design of a public space and the lack of standardized design methods. As the design process progresses and broad outlines are established, more attention is paid to incorporating and designing street furniture, utilities, and materials. Not all details are determined by the public space designer; usually, other professional stakeholders decide on street markings and traffic signals. Complex projects involve many stakeholders. During the design phase, evaluation and decision making are usually iterative steps. As Figure 1a shows, the design phase ends with technical drawings that support the building permit acquisition along with detailed plans that sustain the realization of the infrastructure [7]. As-built drawings support long-term maintenance. The design process has not fundamentally changed since the availability of digital graphics. This research aims to portray whether technology can support citizen participation in co-designing and evolve it into a process, as presented in Figure 1b. It is necessary  
Figure 1: Different phases in the public space design process; the current and proposed process.