An automatic shape modification using surface constraints in CSG.

This paper presents an automatic shape modification method using surface constraints on CSG (constructive solid geometry). In this method, surface constraints are classified into two categories : explicit constraints which belong to spatial relations between CSG primitives and implicit constraints which belong to individual geometric characteristics of each primitive class. The geometric database is composed of two kinds of trees, i. e. a CSG tree and a set of trees representing the explicit surface constraints. The CSG tree and the constraint trees are linked to each other. The shape modification is performed automatically by tracing the trees. A prototyping has proved the algorithm is easy to handle and efficient to execute.