Windows into design

February 2011 » Features » PROGRESSIVE ENGINEERING
Interactive simulator allows people to —€˜drive—€™ the future Presidio Parkway
Kevin Gilson

The $1 billion roadway project won’t be complete until 2014, but the public can sit in the driver’s seat, grip a steering wheel, and enjoy the views and driving experience of the future Presidio Parkway in San Francisco. This is thanks to a pilot simulation study that uses advanced video game technology to create an interactive and highly immersive experience of what’s to come in one of the Bay Area’s most significant current public transportation projects.

Leading up to the Golden Gate Bridge, Route 101, also known as Doyle Drive, travels through the Presidio and the Golden Gate National Recreation Area. Built in 1936, the unsightly 1.5-mile elevated highway no longer meets current highway safety standards and acts as a dividing wall between the Presidio and the San Francisco Bay. More importantly, the roadway is susceptible to significant damage in the event of a major earthquake in this seismically active region. As a result, Doyle Drive is being replaced by Presidio Parkway, a roadway tucked into the contours of the surrounding area that provides increased access to the Presidio and expansive views of the bay.

Three 46-inch monitors mounted 48 inches from the driver create a 150-degree horizontal field of view (FOV) and a 60-degree vertical FOV, providing an arcade-style, yet realistic, driving experience.

Parsons Brinckerhoff developed a virtual driving experience for the new Presidio Parkway to run on an arcade-style vehicle simulator. The simulation was created to showcase this exciting new technology at the 2010 Autodesk University (AU) Conference in December 2010. The system uses commercial video game development tools and established design visualization production techniques to create a simulation that is flexible, cost-effective, and easy to install. Based on the Unreal 3 game engine developed by Epic Games Inc., the simulation features a robust rendering engine capable of creating extremely high-fidelity visuals including advanced lighting, shadowing, and surface rendering that can be modified with minimal programming expertise.

The simulator was designed to provide as immersive and realistic an experience as possible by creating a “window” into the virtual environment. To achieve this, the user’s position in the chassis remains an essential part of the simulator design. The experience comes to life through the use of three 46-inch monitors mounted 48 inches from the driver, creating a 150-degree horizontal field of view (FOV) and a 60-degree vertical FOV that effectively fills the driver’s entire field-of-view.

The simulator chassis uses vibration-backed feedback systems similar to the “rumble” or force feedback features of video games or racing simulators. High-powered speaker drivers are attached directly to the frame, pedal assembly, and steering wheel mounting plate, and translate low-frequency sounds into intense vibrations. Coupled with the chassis’ built-in surround sound system, this creates a surprisingly “real” road experience. In fact, test drivers were prompted to look in the rear view mirror when hearing emergency vehicle sirens from behind — just as they would be in real life.

Project simulations
Simulations for the system are developed as individual, self-contained 3D environments referred to as “levels” or “maps.” Different projects, different locations within a project, or multiple alternatives for a project can be loaded into the simulator sequentially for viewer comparison. These maps are developed in a similar fashion as the multiple levels of a complex video game. But maps for real-world projects such as the Presidio Parkway are developed using resources and workflows similar to those used for visualization modeling and animation development in public outreach efforts. This process takes advantage of the fact that most large-scale transportation projects develop 3D models as part of their ongoing outreach efforts. These assets can be re-purposed relatively easily into content for real-time simulations such as that for the Presidio Parkway.

Autodesk 3DS Max is used to model roadways and surrounding context, and for details such as street signs, vehicles, and landscaping. Geospatial data, including digital elevation models and aerial imagery, are imported and optimized in 3DS Max to produce the surrounding terrain in simulated environments. The final step involves porting the 3D content into the Epic Games’ production environment, the Unreal Development Kit (UDK). Both 3DS Max and UDK provide a wealth of tools to support the optimization of 3D geometry for real-time performance. Lighting and shading, as well as material definitions for 3D content, are all defined and controlled by the UDK engine. Interactivity and artificial intelligence for the various scenarios also are developed using this tool set.

The simulator design was developed initially for another transportation agency project in an effort to represent the in-car driving experience of a proposed new vehicle technology. The California Department of Transportation (Caltrans) and Autodesk saw a demonstration of this technology and jointly sponsored the development of a prototype simulator to be used on several future Caltrans projects. The first content developed for this simulator was the Presidio Parkway model. The simulator and content were shown at AU and soon will be installed in the Customer Briefing Center at Autodesk’s San Francisco office, which is often used by agencies and outreach organizations for meetings and presentations on Bay Area projects.

The simulator was well-received at AU and has generated considerable interest among several agencies, including Caltrans. Development is continuing on the Presidio Parkway model and a model for the San Francisco-Oakland Bay Bridge new East Span. These simulations will be used to give stakeholders an immersive and realistic driving experience of the future.

Kevin Gilson is director of design visualization for ParsonsBrinckerhoff in Denver.


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