Using degrees of freedom analysis to solve topological constraint systems for construction geometry in a computer aided design (cad)

Claim 1

A computer-implemented method for producing a computer-aided design of mechanical parts in a physical assembly comprising the steps of: a) providing a topological constraint system comprising a set of geometric elements corresponding to physical shapes of said mechanical parts, said topological constraint system serving as a template for mating said physical shapes of said mechanical parts in said assembly, said constraint system specifying a set of geometric constraints and topological properties for said geometric elements, b) categorizing states of said geometric elements according to degrees of freedom of said geometric elements; c) categorizing topological properties of said topological constraint system in terms of biases; d) satisfying geometric constraints and reducing degrees of freedom of the geometric elements of the system using the substeps of: i) identifying a geometric constraint that can be satisfied by manipulating one or more of said geometric elements with a computer-implemented constraint solver, ii) implementing by computer said constraint solver, said solver utilizing the geometric element categories and topological properties categories to manipulate said one or more geometric elements into a configuration that satisfies the identified constraint, iii) recording a result of the implementing substep (ii), including a new state of said one or more geometric elements, new values of their respective descriptive parameters, and an identification of the constraint solver implemented; and e) repeating step (d) for a plurality of geometric constraints to produce a configuration of said geometric elements satisfying the constraints in the topological constraint system that can be satisfied by a solver, said configuration corresponding to a design for arranging said corresponding physical shapes of said mechanical parts in said assembly.

Claim 19

A system for producing a computer-aided design of mechanical parts in an assembly, comprising: means for providing a topological constraint system comprising a set of geometric elements corresponding to physical shapes of said mechanical parts, said topological constraint system serving as a template for mating said physical shapes of said mechanical parts in said assembly, said constraint system specifying a set of geometric constraints and topological properties for said geometric elements, means for categorizing states of said geometric elements according to degrees of freedom of said geometric elements; means for categorizing topological properties of said topological constraint system in terms of biases; means for satisfying geometric constraints and reducing degrees of freedom of the geometric elements of the system, comprising i) means for identifying a geometric constraint that can be satisfied by manipulating one or more of said geometric elements with a computer-implemented constraint solver, ii) means for implementing by computer said constraint solver, said solver utilizing the geometric element categories and topological properties categories to manipulate said one or more geometric elements into a configuration that satisfies the identified constraint, iii) means for recording a result of the implementation of the constraint solver, including a new state of said one or more geometric elements, new values of their respective descriptive parameters, and an identification of the constraint solver implemented; and means for repeatedly invoking the means for satisfying a geometric constraint for a plurality of geometric constraints, said means for repeatedly invoking producing a configuration of said geometric elements satisfying the constraints of said topological constraint system that can be satisfied by a solver, said configuration corresponding to a design for arranging said corresponding physical shapes of said mechanical parts in said assembly.

Claim 20

A system for producing a computer-aided design of mechanical parts in an assembly, comprising: means for providing a topological constraint system comprising a set of geometric elements corresponding to physical shapes of said mechanical parts, said topological constraint system serving as a template for mating said physical shapes of said mechanical parts in said assembly, said constraint system specifying a set of geometric constraints and topological properties for said geometric elements, means for categorizing states of said geometric elements according to degrees of freedom of said geometric elements; means for categorizing topological properties of said topological constraint system in terms of biases; means for satisfying geometric constraints and reducing degrees of freedom of the geometric elements of the system, comprising i) means for identifying a geometric constraint that can be satisfied by manipulating one or more of said geometric elements with a computer-implemented constraint solver, ii) means for implementing by computer said constraint solver, said solver utilizing the geometric element categories and topological properties categories to manipulate said one or more geometric elements into a configuration that satisfies the identified constraint, iii) means for recording a result of the implementation of the constraint solver, including a new state of said one or more geometric elements, new values of their respective descriptive parameters, and an identification of the constraint solver implemented; and means for repeatedly invoking the means for satisfying a geometric constraint for a plurality of geometric constraints, said means for repeatedly invoking producing a configuration of said geometric elements satisfying the constraints of said topological constraint system that can be satisfied by a solver, said configuration corresponding to a design for arranging said corresponding physical shapes of said mechanical parts in said assembly.