Real time simulation provides a visual, interactive model that you can easily manipulate.
By Susan Smith
Urban simulation technology has, until recently, seemed prohibitively expensive to most architectural and engineering companies. Although an exciting tool for planning the cities of the future, it was not possible to do simulation on anything less than a $100,000 UNIX-based workstation. Now, you can do very good simulations on a PC using Windows NT--at a hardware cost of between $10,000 and $15,000.
The cost of simulation software promises to come down as well. In the past year, urban simulation software has also migrated to Windows NT. Entry level software can be had for $10,000 to $15,000, still more expensive than CAD, but moving into the more affordable range.
Real time simulation provides a visual, interactive model that you can easily manipulate. It is a valuable tool for the design review process, when clients want to be able to visualize a project quickly and flexibly. Urban areas can be modeled as the need arises; buildings can be added and taken away. GIS data can be incorporated into the simulation, along with photos and CAD data. A simulation allows you to interact with the space and explore areas that you want to see more closely. And if you want to see more detail in something that hasn't been modeled, it takes less than half an hour to go back to the model, make changes, and bring it back into the simulation.
"Not only is simulation visual, but you can interact with it, make changes in minutes instead of waiting hours or even days," says Chuck Hixon of architectural firm Bergmann Associates in Rochester, NY. "With digital animation, I would have to tell the modeler to change the texture, render everything, and see the client in two or three days," he says. "If I show the side of a building with real time simulation, I'll create a texture map or take a picture of the windows and apply it to the surface, so not every window of that building has been modeled. It's implied. With digital animation, you have to model every window."
Technological Evolution
The evolution of urban simulation mirrors that of the GIS industry, in that both technologies were the exclusive domains of the military. Military flight simulator software has been in use for years for military training, demonstrating how cities can be built in a virtual environment for planned attacks. Bill Jepson, the "father" of urban simulation and director of the Urban Simulation Laboratory at UCLA's Department of Architecture and Urban Design, used the same published techniques used by the military and Silicon Graphics' hardware to develop software to explore virtual environments.
Jepson has been working in the area of urban simulation for about 25 years now. Urban simulation is a term Jepson used to differentiate the field from virtual reality. Virtual reality is a more imersive experience where users wear headsets, goggles, and manipulate the objects within the scene.
"Virtual Los Angeles," a simulation demonstrated at A/E/C SYSTEMS '99, is Jepson's personal simulation project. "We started doing single buildings on the computer and it has just grown to where we can do significant sized models of the city for real-time interactive watchers," he says.
According to Jepson, there has been a real need for this type of simulation with cities such as Los Angeles. In fact, UCLA has done about 15 projects to show stakeholders, community members, politicians, and others how new development fits into the existing urban landscape. UCLA works with architectural firms; their projects include an LAX Central Terminal model with beautification enhancements, the UCLA Westwood Hospital designed by I.M. Pei, and the UCLA Santa Monica Hospital designed by Robert Stern.
"Projects have changed dramatically when we've been involved with them," says Jepson. "The client and architects see things they need to change. Evaluations are made based on what we can show."
The Process of Simulation
According to Matthew Cuerdon, AEC market manager for Silicon Graphics, CAD relies on geometry, whereas urban simulations strive to get the geometry as simple as possible to boost performance. The simulation uses textures very heavily, so you need high performance workstations with large texture memory capabilities.
To create a real-time 3D simulation, you need two core types of software-3D modeling software and simulation software. You can use such modeling software as MultiGen-Paradigm's Creator, Autodesk's 3D Studio Max or AutoCAD, or Bentley's MicroStation.
Creator is a 3D modeling software package, whereas the others are designed for engineering and animation purposes. You save your 3D model in OpenFlight format, then put it into a simulation software such as Vega. "Our customers use conversion software packages, such as PolyTrans from Okino Computer Graphics, to convert to OpenFlight," MultiGen-Paradigm's Jonathan Zucker says. "In OpenFlight, users will typically optimize their file for real-time 3D interaction. Without an efficiently organized file, you cannot allow the computer to draw the scene at high frame rates."
Urban simulation is much more macro-oriented than other types of simulation. Obviously, it runs on a large scale, and usually displays exteriors. "The real-time 3D model's structure is much simpler than the AutoCAD 3D model," Zucker says. He adds that when visualizing a project in 3D, it makes sense to start simple, then get complex.
But most architects today have an existing CAD modeling or animation package that they rely on. They have digital terrain models (DTMs), DEMs or USGS data from a GIS, plus photos from different sources. The process of 3D design has always been complex and slow. "Animation and rendering software packages are not concerned about drawing at high frame rates," says Zucker. "These programs spend up to an hour per frame rendering to attain a high level of realism, and the complexity is significant. Everything you do in Creator is focused on real-time 3D and is organized for drawing at a very high frame rate while attaining the highest visual quality possible."
Whichever way you approach the simulation, at some point you must make a choice. "If you choose to go down the real time path and want to re-use existing 3D data, then you will likely have to purge some content from your AutoCAD file," explains Zucker. "If you continue down the path of AutoCAD, then choose later on to convert this data to a real-time 3D format without any optimization, it's going to hurt your real time performance significantly."
Project Simulations
Mike Rosen of Mike Rosen & Associates is well known for the ModelCity Philadelphia project, which uses MicroStation. During the past year, Rosen has been working on project specific sites. "We take urban projects that are being planned for Philadelphia and help the clients visualize the projects within the city," he explains. "The most significant of which is the baseball stadium for the Phillies."
This simulation proved priceless, as it saved money during the design of an opening that allowed you to see the Philadelphia skyline. "When we built the model and got down onto the field and looked toward the sky, we realized the cut in the stadium was in the wrong place," says Rosen. "The huge scoreboard hid a piece of the city." They moved the stadium over 40 feet and rotated it so they had the design and view they wanted. "There was no other way to visualize that problem until the stadium was built," he says. "By then it would have been too late."
Mike Rosen & Associates are well aware that many cities are discouraged by the costs associated with urban simulation, so they are exploring technologies that will save money and time. Already, there is progress. "What used to take us a year now may take us a few weeks," says Rosen.
VPST Inc. won approval to do a virtual reality model of the Fourth Floor Preparation Theater for the new Smithsonian National Museum of the American Indian. "We're working with their designers in creating the simulation of one of their theaters so they can evaluate different schemes, exhibit layouts, and color palettes," explains Dennis Cafiero, VPST virtual environment architect.
If you think that urban simulation is only for large cities or government entities such as the Smithsonian, VPST has another project in collaboration with E.T. Boggess Architects to do an entire downtown area simulation for a revitalization project of Princeton, WV, a small urban town. Although the funding for this project has come largely from government grants, donations have also come from the town's industry, as well as private citizens.
Engineering & Computer Simulations Inc. (ECS) of Orlando, FL, has done work for Miami International Airport, Newark International Airport, and others. The firm uses real-time simulation to plan airports, rail, and interior design. Using airport schedules from the Federal Aviation Administration's SIMMOD (Airport & Airspace Simulation Model), ECS simulates the air and ground traffic around the airport during a 24-hour period. It also conducts noise contour analysis to see how noise will affect different areas.
Mike Sherman, CAD manager of the National Capital Planning Commission (NCPC) in Washington, DC, is involved with the planning of the future development of the capital city. NCPC reviews development proposals and master plans that impact the federal interest in the metropolitan Washington, DC region, such as memorials, museums, monuments, and other facilities. NCPC has created the Legacy document that outlines a vision of Washington for the millennium and builds upon the original layout plans for the city.
"Our design review schedules are short. We have 30 days to get a project in and 30 days to review it, then we're on to the next project," he explains.
Slowly, NCPC is developing a 3D model of various parts of the city. "My goal is to get a highly accurate DC model so anyone who has a need can get the data from us for their use," Sherman says.
Integrating GIS Data
A remarkable project in progress is the effort of the nonprofit Orton Family Foundation. It is funding a software development team headed by the Environmental Simulation Center. PriceWaterhouseCoopers is developing the policy simulator module, MultiGen-Paradigm, the interactive 3D module; and Fore Site Consulting, the scenario instructor/impact analysis module. The Community Planning and Simulation Project toolkit is code-named Community Works.
Community Works is expected to be more than a visualization tool for GIS data. It will allow a community to formulate growth management policies to plan and design different growth scenarios, and gauge the impact of growth on housing and population 20 years hence. The prototype Community Works tools will consume GIS data and convert it into 3D data. Currently, a 3D GIS software application lets the user view the data in 3D, change the data in 3D real-time, then update the GIS database accordingly.
The Orton Family Foundation has picked ESRI's ArcView GIS software package to link to. Using their GIS, a town will be able to select layers that they want to visualize, easily generate a real-time 3D world from this data, fly or walk through those layers, and add or remove buildings without ever losing their connection to the 2D GIS database.
"The seamless integration of GIS with real-time 3D interactive visualization, policy simulation, and impact analysis software will revolutionize community planning and design-decision making," says Michael Kwartler of the Environmental Simulation Center.
Other Tools
Fakespace produces hardware, software, and complete systems for immersive visualization and virtual reality. The company's VLIB software library provides links to a variety of software applications. Since the software is a background library and device driver, it doesn't have to be industry specific like an application.
The Immersive WorkRoom and Immersive WorkWall are large-scale visualization environment tools that enable group viewings of flythroughs or walkthroughs. The Immersive WorkRoom is a 10-foot cubical structure that displays 3D projected images on its walls and floor. The Immersive WorkWall is a 24-foot wide solid screen flat wall display system.
"This summer, Fakespace is introducing some innovative navigational devices for use with the Immersive WorkRoom and the Immersive WorkWall," explains Jim Angelillo, president of Fakespace. "These tools make it very easy for non-technical personnel to navigate within 3D virtual environments."
Another fully immersive environment is a "cave." VPST partners with VT-CAVE, or University Visualization and Animation Group of the Advanced Communications and Information Technology Center, and Virginia Tech Intellectual Properties (VTIP). The university has a cave that provides a high resolution virtual environment for testing detailed designs and detecting errors early on in the design.
Data Translation Issues
Cafiero says MultiGen's OpenFlight file format, FLT, is to virtual reality what DXF is to CAD. He recommends 3D Studio Max because, he says, every simulation application supports 3D Studio Max and AutoCAD, and those products export VRML. VRML runs in the cave.
Cafiero explains that in AutoCAD Design 2000, if you make changes in a file it all links together with no loss in translation to 3D Studio or other Autodesk products. However, simulation packages sometime require editing of the models. "Usually something in the model causes it to go wrong," he says. "So you bring in pieces of the model instead of the whole model at once."
A program like 3D Studio Max can treat NURBs as smooth surfaces. But when you bring the 3D model into the simulation package, it takes all the surfaces and triangulates them; each one is treated as a polygon. MultiGen-Paradigm distributes a product called V-Simplify from Virtue 3D Inc. in San Jose, CA, that works on an OpenFlight format. When you put the file into Creator, V-Simplify will then do automatic polygon reduction on the file.
Jepson says they use CAD data as a skeleton only, then rebuild the models on top of that with their own system, which is called the Urban Simulator.
It is already possible to be able to export real-time data into other 3D environments, Zucker says. You can export files as DXF from a simulation originally modeled in Creator. "When you have reached consensus on a design, then you take your real-time model into 3D Studio, do a high quality animation, and take the model into AutoCAD to do your construction drawings," he explains.
Costs
The time available, skill level of the operator, equipment used, and required quality of detail all contribute to how costly the simulation becomes, according to Sherman. If users are well versed in 3D modeling, then the stretch to working with urban simulation isn't as great for them.
The cost of higher end graphics cards with more memory is now lower. Many new programs are being written in Fahrenheit, an application programming interface (API) being developed jointly by Silicon Graphics and Microsoft that will allow the portability of simulations between a PC platform and UNIX.
Virtual Reality Centers
The growth of virtual reality centers also helps lower the cost of urban simulation. A case in point is the new Virtual Environment Technologies Centre (VETC) designed by the Integrated Manufacturing Technologies Institute (IMTI) of London, Ontario. Dr. Gian Vascotto, research director at IMTI, says that the Institute is one of three National Research Counsel (NRC) of Canada's institutes devoted to technologies that will make Canadian manufacturers more competitive.
"We realized that unless we had a facility available to learn from and explore, then we would have a tough time competing in the future," Vascotto explains. "We had requests from 100 companies who were interested in workshops on the technology. There was an overwhelming interest from the AEC segment in forming a technology group to address AEC issues."
Moving to the PC
Although running a simulation on a PC is possible, and cheaper, it's not yet as desirable as using a high capacity machine, Cafiero says. "If we're working on a PC, we have to edit the data quite a bit," he explains. "You have to consider the more detail in a model, the more polygons are in the model, and the slower the simulation will run."
This will not be the case for long. "Every 18 months the speed of computers is doubling," Cafiero says. "So now we have the ability to support more polygons and larger scale models."
Jepson says that for smaller projects, the PC provides the quality they demand. For large projects, they still work on a UNIX workstation because they won't be able to get the quality, scale, and realism they need on anything less.
The Future
For MultiGen-Paradigm, conducting real-time 3D walkthroughs via the Internet, and being able to shorten modeling time by leveraging technologies that will create 3D models from both satellite and video imagery are top priorities. "We're looking at technology that will interrogate the satellite image and extrude and extract 3D models from it, as well as from the video camera," Zucker explains.
Cuerdon predicts, "Over the next few years, I believe the focus will be collaboration between the urban simulation software vendors and the CAD software vendors, so that the data developed in the urban simulation phase can flow into the design phase."
Will real time simulation replace digital animation? "Absolutely," claims Hixon. "The only thing prohibiting that right now is technology, both hardware and software. "You don't have to invest $100,000 to do this anymore."
Fakespace Inc.'s Immersive Workroom has been installed at Canada's first Virtual Environment Technologies Centre, which was built for the National Research Council of Canada with the goal of providing tools to make Canadian industry more competitive in global markets.
Perhaps one of the most profound simulation products to be seen is muSE (pronounced muse), from MUSE Technologies Inc. in Albuquerque, NM. What muSE stands for is "multidimensional user-oriented synthetic environment." It is designed around the human mind. The user interface is designed to flow with a user's personal internal processing system. It is device independent, real-time in operation, and supports network-based, heterogeneously shared environments. The system currently supports a variety of devices, plus flat screen, stereo, and VR operation, voice recognition, sound synthesis, and data sonification.
The product is a powerful user interface that enables the integration of many different types of data into a single interactive synthetic environment. muSE is used for information analysis, simulation testing, and visual presentation programs. In the area of transportation, topographic, geometric, and photographic data has been combined to create a model of highways, as in the case of TranSims, a simulation of a proposed highway system through Dallas-Fort Worth.
Third party developers can develop their applications under the product's application development system.
Some of the 250,000 vehicles in this simulation sit at an intersection; the red and green boxes indicate traffic-light status. The green cars' trip plans end at the mall; the blue cars' elsewhere. The cyan car has been selected by the user. This view of the data gave TranSims analysts insights about traffic overall as well as car-to-car interactions.
This view shows aggregate traffic plans for every vehicle traveling to or through the mall area. Green and red peaks indicate directions of travel. Analysts determined that the largest concerntration of traffic was near the mall, but not necessarily mall-bound.
The Evans & Sutherland RAPIDsite system is a new photorealistic 3D visualization tool for those architects and engineers who want to create an interactive, photorealistic model of an area up to 50 acres, including 50 new and existing buildings. RAPIDsite bears mentioning here because it is an innovative, low cost, easy-to-use solution to the problem of providing big picture viewing and analysis of building sites before plans are finalized. RAPIDsite Explorer is the base product that supports interactive exploration and presentation of photorealistic environments. It also supports importation and positioning of 3D models within the virtual environment. RAPIDsite Creator supports model creation for terrain, vegetation, new and existing structures, and panoramic backgrounds. RAPIDsite imports data from CAD, GIS, and other environments. "We start with CAD data and we have a tool that uses that data as a template to construct simplified geometry," explains Chuck Clark, director of marketing for the Pixel Products Division at Evans & Sutherland.
Susan Smith is Executive Editor of A/E/C SYSTEMS: The Magazine of Computer Solutions. She can be reached at 505/989-4947; Fax: 505/986-3816; susith@aol.com
From A/E/C SYSTEMS, Summer 1999