Offsetting operations in solid modelling

The range of operations on solids supported by current geometric modelling systems is very limited. Typically, solids represented in a modeller can be transformed by rigid motions and combined by Boolean operations. This paper introduces another family of transformations, called solid offsetting, which map solids into solids. Offset solids are expanded or contracted versions of an original object. Offsetting operations are potentially useful for tolerance analysis, clearance testing, design-rule checking in VLSI, modelling of etching and coating processes, cutter path generation for numerically-controlled machine tools, collision free path planning for robot motions, and for constant-radius rounding and filleting ('blending') of solids. This paper discusses mathematical properties of solid offsetting, associated representations and algorithms, support of offsetting operations in solid modellers, and applications, Results of an experimental implementation are presented.