Boundary evaluation in non-manifold environment

摘要

An information processing system performs boundary evaluation in a non- manifold environment. The system may be used for representation of objects in three dimensions, in a very general manner. Objects are represented by merging boundary representations of constituent sub objects, and selecting portions of the resulting merge boundary representation. Selection is based on criteria applied to a containment history of each portion of the merged boundary representation.P PA data structure suitable for boundary evaluation in a non- manifold environment includes a constructive solid geometry tree and a boundary representation. The boundary representation further includes boundary descriptions, a list of regions, containment histories of each region and a mark indicative of selection or non-selection of each region.