Building Solid Models from Polygonal Data

Boundary representations (BRep) of three-dimensional solids are complex data structures that have to be created with topological and geometrical integrity. In many applications, the boundary of a solid may he specified as a list of polygons. In this paper, we consider the problem of constructing a BRep solid model from a list of polygons with the assumption that the points of each polygon lie in plane within some small tolerance, that two polygons do not penetrate each other, and that together the polygons enclose a volume. The algorithm works with any boundary representation based on direded edges and capable of representing nonmanifold edges and vertices, and accommodates a measure of numerical inaccuracy. lTbis work has be= supported in pm-l by NSF Grant CCR.86-19S17 to Purdue Universily.