A Workbench for Geometric Constraint Solving

Abstract

Geometric constraints are used in geometric and feature modeling systems to impose conditions on the shape of a product. To determine whether these conditions are correctly applied to a model, and to compute the final solution in which all conditions are satisfied, a geometric constraint solver is used.

Current constraint solvers usually handle only 2D constraints. With the introduction of solvers that support 3D constraints, the interaction and visualization techniques for 2D constraints are no longer sufficient. Also, the feedback provided by the 2D constraint solvers, especially if problems are not well-constrained, is limited and not applicable to 3D modeling environments.

In this paper, a workbench is presented that can assist a user in defining geometric constraints in 3D and in creating a valid 3D model. Feedback provided by the solver is presented to the user in several ways that enable him to easily interpret this feedback.

Keywords:

• geometric constraint solving
• graph constructive approach
• sketching
• visual feedback