Reconstruction of CSG solid from a set of orthographic three views

An interpretation method of orthographic three-views of a mechanical drawing based on dividing operations into primitive volumes is presented. The method outputs a constructive solid geometry (CSG) solid model composed of a binary tree of direct sum and difference operations for object shapes limited to combinations of six primitives. The main parts of the method are to extract all loops, to obtain the combinations of the loops of 2-D primitives for each view, to generate all possible combinations of 3-D primitives, and to generate a CSG tree of the direct sum and difference operations on them. The algorithm is described, and some examples are shown.<>