Immersed in design

Computer scientists at the University of North Carolina (UNC) are helping architects and engineers to create extremely detailed virtual structures that designers can ‘walk through’.

The WalkThru Project, led by UNC computer science professors Fred Brooks and Dinesh Manocha, is funded by the US National Science Foundation (NSF) Division of Advanced Computational Infrastructure and Research. The UNC team develops new algorithms and software for advanced prototyping that could yield safer yet more cost-efficient buildings and vessels.

‘The overall goal is to create interactive computer graphics systems that let a viewer experience complex 3D spatial models by simulating walk-throughs of the actual facility,’ said Brooks, who started the project in the mid-1980s.

The computer scientists take very large CAD/CAM models and render them as fully navigable 3D environments, including a tanker with 82-million separate elements and a 13-million-element electric power station. Until now, such complex virtual structures yielded slow, jerky graphics that did not permit real-time navigation and manipulation.

Cosmetically, the WalkThru tanker simulation has a level of technical realism that more than equals anything Hollywood has done. Its 3D space is said to be completely navigable from stem to stern, consisting of 82 million triangles.

Synthetic environments that succeed in providing a realistic experience for their users can also be used for collaboration between design teams separated by distance.

‘One of the challenges is to develop a scalable system to achieve real-time walkthroughs of very large CAD/CAM models with high-accuracy rendering of spatial arrangements,’ Manocha said. ‘We write efficient algorithms to accelerate rendering and improve collision detection, as when the user ‘bumps’ into a stationary structure.’

CAD/CAM and architectural models may contain millions of small 3D elements, called ‘primitives.’ To display these models at interactive rates, developers must write algorithms to reduce the number of primitives that the graphics system is required to render.

The team is also developing algorithms to assign processor priority according to each element’s visibility, which permits users to see and interact with the model at a greater level of detail.

Although WalkThru Project models were developed on advanced graphical workstations made by Silicon Graphics, they will also run on high-end PCs. The walkthroughs can also be viewed in immersive virtual reality caverns that let the user experience the simulations on a life-size scale.