Subodh Kumar Shankar Krishnan Dinesh Manocha Atul Narkhede
Department of Computer Science
University of North Carolina
Chapel Hill NC 27599
We present a system for fast and accurate display of
CSG (constructive solid geometry) models. Such models have as
primitives, polyhedra and solids whose boundaries can be
represented using rational spline surfaces.
%The latter set includes cones, spheres, tori, solids of
%revolution, prisms, pyramids etc.
As part of pre-processing, we compute the B-rep (boundary
representation) from the CSG tree and represent the resulting
solid using trimmed spline surfaces.
No assumptions are made on the number of primitives or
the degree of the primitives in the CSG tree.
We also present an accurate, efficient
and multiresolution representation of the high degree trimming curves.
Given a trimmed spline model, we tessellate it into polygons as a
function of the viewing parameters and render it using
visibility computations and coherence between successive frames.
The choice of a multiresolution representation of the model and the trimming
curves is {\em fundamental} to the fast performance of the system.
The system has been used to convert parts of a submarine storage and handling
system model represented as more than $2,000$ CSG trees. The B-rep consists
of more than $30,000$ trimmed spline surfaces and is displayed at
interactive rates on the Pixel-Planes 5 graphics system.
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Supported by DARPA ISTO Order No. A410, ONR Contract N00014-94-1-0738, NSF Grant No. MIP-9306208,
Junior Faculty Award, University Research Award, NSF Grant CCR-9319957,
ARPA Contract DABT63-93-C-0048 and NSF/ARPA Science and Technology
Center for Computer Graphics and Scientific Visualization, and NSF Prime
Contract No. 8920219.