vLOD: A Scalable System for Interactive Walkthroughs of Very Large Virtual Environments

Jatin Chhugani   Budirijanto Purnomo   Shankar Krishnan   Jonathan Cohen    Subodh Kumar   


The problem of interactively rendering and navigating very large virtual environments has been well-studied in computer graphics. The two effective methods for efficient rendering of large polygonal models are to conservatively discard invisible geometry early in the pipeline and to remove unnecessary detail not discernible from the current view-point. There have been significant advances recently in both these areas independently but few comprehensive methods have been shown to derive maximum advantage of both methods at the same time. We present vLOD, a scalable system for performing interactive walkthroughs of very large geometric models on com-modity graphics hardware. Our system performs work proportional to the required detail in visible geometry. We use a pre-computation phase to determine cell based visibility as well as level-of-detail. This pre-computation generates the geometry visible from a view cell at the right level of detail. We encode changes between neigh-boring cellís vLOD, which is not required to be memory resident. At rendering time, we incrementally re-construct the vLOD for the current view-cell and render it. Due to the small run-time overhead, we are able to display models with over tens of million polygons at interactive frame rates with less than 1 pixel error.

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Accelerated Walkthrough of Large Spline Models
Subodh Kumar    Dinesh Manocha   Hansong Zhang   Kenneth Hoff  


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Interactive Display of Large Solid Models for Walkthroughs.
Subodh Kumar     Shankar Krishnan     Dinesh Manocha    


IEEE Computer Graphics and Applications, March 1996. Not available online.