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Originally published in the Summer 2002 Virginia Tech Research Magazine.

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Shaking up things in virtual reality

By Sarah Newbill
College of Architecture and Urban Studies

Two researchers studying a structure in virtual reality (photo)

Two researchers studying a structure in virtual reality.

Architecture Professor Mehdi Setareh and his research team are creating tools to help building design and construction professionals analyze a structure’s stamina, even before it is built. The team has developed a computer program that will help architects, builders, and contractors save time and money — and possibly lives.

The user can build a structure in virtual reality, subject it to an earthquake or other load, and immediately see hard data on how the structure fared. “You can make design changes right there on the spot, changing the orientation of the columns, for example, and subject the building to another low to moderate earthquake and see how it changes the behavior of the building,” says Setareh, principal investigator on the project.

The Virtual Structural Analysis Program (SAP) is being developed as an interactive collaborative design tool providing an environment that users can walk through and immediately observe the consequences of their design alterations. “This is not just a visual thing. There’s hard data to back up what is actually occurring. The movement of the building and its different elements are measured and recorded by the program, calculating how much the structure is going to move,” says Setareh.

There has been a lack of available software in the architecture/structural engineering field that can provide both high-quality graphic appeal and computational abilities. Some programs create high-resolution graphics, but don’t have a computational aspect. Some analyze the effect of different loading conditions on structures, but are not user-friendly or suitable for use by non-technical individuals. Virtual SAP closes the gap between the two and adds the extra appeal of “being there” in a virtual environment (VE), giving the user a sense of scale and providing real-time data.

Future applications include use in evaluating post-disaster structural problems. “If you want to check a partially collapsed building for stability, you have to hunt down the drawings, wherever those may be. If you have something like this program, you can easily incorporate not just the structure, but the mechanical and electrical systems, plumbing and wiring, and see where the problems and safety issues are. We have created the connection between the graphical aspect and the engineering aspect.”

The program can be used on the desktop, controlled by a mouse and keyboard, to allow the whole design team to view the structure at the same time. But, to get a better sense of the scale, shape, and movement of the structure, the individual VE interface is best. The user wears a head display and holds a special pen in one hand and tablet in the other. Through the head display, the user sees a virtual pen that will be used with the tablet that now shows a virtual interface of buttons and menus for creating the structure. Objects can be selected with the pen from the tablet, then dragged and dropped to new locations, snapping into a three-dimensional grid to allow for precise placement.

“There is a 2-D interface working inside the 3-D interface,” says Doug Bowman, assistant professor in computer science at Virginia Tech and an investigator on the project. “It’s kind of like having a Windows interface that you can carry around with you in the virtual environment. The 2-D interface (the tablet) is the way you do a lot of the simple tasks like create a column. But there’s also a 3-D interface — for example, you can reach out and grab an existing column and move it somewhere else.”

The user can also fly around the virtual world to view the structure from any point, both inside and outside the model during and after the building process, or after it has been subjected to an earthquake. Plans are to link to a motion platform in the virtual environment so a user can go to different levels of the building and get a feel for actually being in an earthquake, says Setareh.

The National Science Foundation provided initial funding for the research in 1999 and recently awarded funds to support an undergraduate architecture student who will learn advanced computer graphics skills, then work with the team to create objects and components.