Patent ID: 11928391

Abstract:
Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of structures include, in one aspect, a method for hybrid surface modelling with subdivision surfaces and NURBS surfaces, the method including: modifying a control mesh (in accordance with received input) of a subdivision surface model including a topological control that tracks mesh to NURBS relationships for a limit surface of the subdivision surface, and stored NURBS surfaces representing the limit surface; obtaining an updated limit surface from the modified control mesh; finding at least one modified NURBS surface in the stored NURBS surfaces in accordance with relationship(s) tracked in the topological control; and for each modified NURBS surface, updating the modified NURBS surface with its corresponding replacement NURBS surface, and applying at least one geometric modification (associated with a modified NURBS surface in a history procedures system) to the associated modified NURBS surface after its update.