By: Roy Chan, Urban Simulation Specialist
MultiGen-Paradigm, Inc.

Urban Simulation, a three-dimensional real-time visualization process, is becoming an increasingly important tool for architects in the design and development process. As the technology becomes increasingly affordable and accessible, its use will quicken the development process. With Urban Simulation, design flaws are detected early, concepts are understood sooner, and ultimately, development costs are reduced before the commencement of construction. Real-time simulation takes a bold and effective step in quickly empowering both the designer and the client to fully understand a building well before it is built. While many firms use 3D visualization technology as a presentation tool, Urban Simulation creates the potential to streamline all phases of an architectural project from schematic design to construction and maintenance.

What is Urban Simulation? It is a rather new 3D computer technology that offers the ability for one to quickly model existing and new buildings within their context and be able to interact in the environment at will as the computer renders the scene in real-time (15-30 frames per second). Buildings, trees, streets, sidewalks, lampposts are represented through the use of digital photo-textures that are "pasted" on the 3D models. Unlike a non-interactive animation, or still rendering applications, real-time simulation will allow one to walk, drive, or fly anywhere in an existing neighborhood that is fully textured with images of concrete, wood, brick, grass, etc. With the use of a mouse or joystick, one can walk up to a proposed shopping center, enter into the building, go up the escalator to the second level, walk up to proposed storefront designs of commercial tenants, and look up at the skylights and trusses hanging from the ceiling.

There are some items that are essential in the development of an Urban Simulation model. Necessary software for this undertaking includes a real-time 3D modeler and optimized viewer (known as a run-time), such as MultiGen-Paradigm's Creator and Vega products, respectively. The modeler is the creation tool for the 3D environment and the viewer is the interactive environment that the user moves through. For hardware, an affordable Pentium-class PC with an accelerated Graphics card is required. Of course, increased horsepower on the PC adds to the performance and provides for additional complexity in a simulation. Furthermore, adequate source data is important, such as building and site dimensions as well as photographic textures of architectural elements. Finally, CAD models and aerial photographs of the site are helpful source data to quicken the real-time modeling process and add more context to the environment.

For both the architect and the client, Urban Simulation's ability to quickly visualize and experience a proposed building in real time is a powerful tool that works effectively within the multiple facets of a project.

Submitting Proposals
When a request for proposal goes out for a project, each architect in contention is leveraging the best presentation techniques to convey the firm's expertise, style, and use of innovative tools. Leveraging Urban Simulation technology, a firm can offer a visually stunning presentation that engages and involves the audience to convey the firm's understanding and approach to the project as well as commitment to cutting-edge technology. Furthermore, the firm can uniquely offer clients the ability to interactively see a design in 3D and empower them to make informed decisions early on. As a result, the firm's unique service of real-time 3D visualization can accurately represent a firm's commitment to a proposed project and serve as a competitive advantage to secure new business.

Programming and Pre-design
When an Architect is working out the program requirements for a project with the client, he/ she traditionally works with abstract bubble diagrams that are hand-drawn to convey space relationships involving use, circulation, and square footage. By quickly creating a real-time 3D model, the architect can immediately represent three-dimensional form from program requirements and visually experience these important relationships, which become the basis for the design. For instance, circulation requirements for a restaurant project may call for the public and private space to be linked by semi-public and semi-private space of specific area ratios. With various line types that link different bubbles representing rooms, the architect would, for instance, link the public entrance to the public dining room to the semi-public hallway to the semi-private kitchen to the private office. With just a little more time, a real-time 3D visualization of these relationships can be modeled for the proposed site and viewed interactively. Here the architect can literally walk the client through space relationships, and issues of scale, circulation, and even form can be discussed effectively at this early stage in the project. Because real-time 3D technology renders in frames per second, program requirement changes resulting from these discussions can be quickly implemented into the model and then viewed interactively. This iterative process quickly creates a very realistic sense of the design alternatives and immediately engages the client to make informed and cost-saving decisions from the outset of the project. This effort results in a shortened design time and lower project costs.

Schematic Design/ Design Development
The 3D model created in the pre-design phase can then be evolved into schematic design and design development. The architect can immediately visualize floor plans, elevations, and sections by further developing the 3D model and then experience the space from literally every possible angle or eye point. 2D renderings can easily be scanned and pasted onto the real-time model to be viewed interactively. The architect's traditional creation of proposed color and material sample boards can be enhanced by transferring photographic images of these materials as textures to be pasted onto the model. These images can be obtained from actual places by a digital camera. Furthermore, many digital photo-textures can be obtained by vendors such as grass, colored concrete, slate, brick types and incorporated into a texture library. By having a textured model of a restaurant within its context, a client can then walk around and through the building from a pedestrian point of view and understand what it will feels like to experience the space. A very exciting element of Urban Simulation includes functionality whereby a proposed beige brick facade can be instantaneously replaced by other materials such as wood siding or slate tiling. Window placement can be changed to maximize important views that were discovered by the simulation. These are just some of the ways the technology can interactively explore design alternatives and minimize design flaws that are only understood from such an interactive environment.

Construction Documentation
After a design has been developed, the architect can use the 3D model to aid in the development of a set of construction drawings by understanding the implications of how structural elements are put together in 3D. Detailing connections such as a spiral stairway between two floors can be understood better though an immersive environment that will allow the draftsman to walk up that stairway and view its relationship to both floors from limitless angles. Moreover, much like a multi-layered set of CAD drawings, the 3D model can serve as a communication tool between the architect and engineering consultants in order to understand how electrical, plumbing, mechanical, and structural elements all relate to each other. 2D CAD data that spatially represents these systems can be added to the 3D model to visualize the spatial relationships. As the technology adapts to the application, hyperlinks can be created between 3D elements and corresponding CAD drawings. For instance, picking a door in the real-time 3D environment would then display the CAD drawings that represent the exact door in the floor plan, elevation, or door schedule of the construction documents. Furthermore, picking a particular wall in 3D would open the CAD drawing of the wall section showing the sized studs, sheathing type, insulation, and finish material. These are just some of the application possibilities that Urban Simulation allows in the process of construction documentation.

Government Approval Process
When a controversial project is brought before a public hearing or commission meeting, the designer's ideas are often misunderstood. This occurs primarily because a 2D-site plan, an artist's rendering, a video fly-through or even a physical model can not fully represent the implications of a design to a collective body of laypeople. However, a fully interactive 3D-textured environment will immediately engage the audience and create a common visual language whereby all stakeholders of the project can understand and dialogue from. Members of an audience can direct the visualization to a particular part of the model that may be controversial to more effectively create discussions in a common visual context. Even the planning department or building department can be empowered to better understand a project's impact by visualizing alternatives through the real-time environment. An Environmental Impact Report can be much more effectively communicated by using snapshots from a real-time 3D model that can be taken from any angle in the model to clearly show various levels of impact from limitless perspectives.

Contract Administration
Urban Simulation can be used to present a development to contractors in order to foster more accurate cost projections and bids. It aids contractors in offering better construction techniques by allowing them the ability to experience a 3D real-time model of a building that can be linked to construction drawings and written specifications. The use of the technology can greatly mitigate the need for change orders as unworkable construction issues are realized early on. Furthermore, it allows the architect and contractor to understand impacts to the structure resulting from unforeseen change orders and empowers the developer to make better decisions with the construction budget. Finally, Urban Simulation serves as powerful 3D visual language for the architect, engineers and contractors to communicate on the same playing field. Potentially, this 3D environment can create an interactive virtual construction site where all members of the project team can walk through and discuss issues without all physically being at the actual site.

Post-Occupancy
There are many post-occupancy applications for a real-time 3D database. First, any remodeling or additions made to the structure can be explored easily with an existing 3D model as it was constructed. The architect can document proposed and actual changes of a building, and ultimately keep track of the life of a building over time. Through this documentation, building maintenance can be made efficient by the model's ability to spatially represent waterlines, electricity, mechanical systems, structural integrity, circulation flow, and interior design changes. A developer can also make use of the 3D model as a marketing tool to attract tenants, while a municipality can interactively show to the public a design for a community center before it's built.

Urban Simulation serves as an extremely effective tool in the multiple phases of a project. It is a way to experience the future and mitigate negative impacts, design flaws, and unnecessary costs of development. Moreover, it creates a visual language that fosters clearer communication about form, space, and use of a place, breaking down the walls that often divide the architect and the client/ public. As the technology of real-time visualization and hardware capability rapidly improves in the twenty-first century, Urban Simulation will ultimately revolutionize the profession and perception of architecture, much like the impact of CAD technology. Thus, it is essential that responsible design professionals leverage this already powerful technology to set a strong foundation for this emerging application.