Representation and interpretation of geometric tolerances for polyhedral objects. II. Size, orientation and position tolerances

This article presents a computational scheme for representing and interpret ing the geometric tolerances (mainly size, orientation and position toleran ces) assigned to polyhedral objects. The proposed representational scheme i s based on a surface-based variational model. Variations are applied to a p art model by varying each surface's model variables. Those model variables are constrained by relations derived from tolerance zones. This article add resses two questions: (i) how to describe the tolerance zones according to different tolerance specifications? and (ii) how to vary the model variable s when the variational models (of the part) are instantiated? The scheme ha s been fully implemented in an object-oriented programming environment. (C) 1999 Elsevier Science Ltd. All rights reserved.