Body-and-cad geometric constraint systems

Motivated by constraint-based CAD software, we introduce a new, very general, rigidity model: the body-and-cad structure, composed of rigid bodies in 3D constrained by pairwise coincidence, angle and distance constraints. We have identified 21 relevant geometric constraints and a new, necessary, but not sufficient, counting condition for minimal rigidity of body-and-cad structures: nested sparsity. We remark that the classical body-and-bar rigidity model can be viewed as a body-and-cad structure that uses only one constraint from this new set of constraints.

• Type: Conference
• Year: 2009
• Where: SAC
• Authors: Kirk Haller, Audrey Lee-St. John, Meera Sitharam, Ileana Streinu, Neil White
• Keywords: Applied Computing, Body-and-cad Structure, Relevant Geometric Constraints, Rigidity Model, SAC 2009