Abstract: A method, useful in computer-aided design, for finding configurations of collections of geometric elements representing shapes of physical objects that satisfy a set of geometric constraints, when these constraints relate to topological properties of the geometric elements. In particular, the invention relates to a method that classifies the geometric elements in terms of degrees of freedom, categorizes topological properties in terms of biases, and synthesizes a solution by progressively reducing the total degrees of freedom in the system.

Abstract: A system and method for geometric modeling particularly useful for conceptual design in a mechanical CAD system. Geometric modeling includes not only geometric information, but other engineering and design constraints as well. The present method solves this geometric constraint satisfaction problem using graph based solution techniques. Constraints are graph sources of dimensional, translational, and rotational degrees of freedom while the geometric entities in the model are graph sinks. The method generates an ordered dependency list of geometric entities by allocating degrees of freedom according to a geometric entity's ability to absorb them. The ordered dependency list is used as an execution sequence if a constraint is changed. If a constraint or geometric entity is added or deleted from the model, the ordered dependency list is recomputed. A modeler can thus conceptualize incremental changes in the model while satisfying the imposed constraints.