Patent ID: 11928391
Assignee: AUTODESK, INC.
Field: Computer technology (Electrical engineering)
Classification: CPC G  B | IPC B  G

Claim 18:
19. A non-transitory computer-readable medium encoding instructions operable to cause data processing apparatus to perform operations comprising:
generating a subdivision surface model of a subdivision surface, the subdivision surface model comprising
a topological control structure that tracks relationships between respective portions of a control mesh of the subdivision surface and stored NURBS surfaces representing a limit surface of the subdivision surface, and
a subdivision surface data structure comprising the stored NURBS surfaces representing the limit surface;

receiving a direct edit of at least one of the stored NURBS surfaces performed using a NURBS modeling tool, which forms at least one modified NURBS surface in the stored NURBS surfaces by application of one or more geometric modifications;
associating the one or more geometric modifications, which correspond to the direct edit of the at least one of the stored NURBS surfaces, with the at least one modified NURBS surface;
receiving input to modify the control mesh of the subdivision surface model of the subdivision surface;
modifying the control mesh in accordance with the input to form a modified control mesh;
obtaining an updated limit surface from the modified control mesh;
finding the at least one modified NURBS surface in the stored NURBS surfaces in accordance with one or more of the relationships tracked by the topological control structure, the at least one modified NURBS surface having a replacement NURBS surface in the updated limit surface;
updating the at least one modified NURBS surface in the stored NURBS surfaces with the replacement NURBS surface;
applying the one or more geometric modifications to the at least one modified NURBS surface in the stored NURBS surfaces to reapply the direct edit previously performed using the NURBS modeling tool; and
processing the stored NURBS surfaces, at least one of which has been updated by the input to modify the control mesh of the subdivision surface model, for output by a physical device.