US 11,928,391 B2
Hybrid surface modelling with subdivision surfaces and NURBS surfaces
Dan Mircea Lupas, Mississauga (CA)
Assigned to Autodesk, Inc., San Francisco, CA (US)
Filed by Autodesk, Inc., San Francisco, CA (US)
Filed on Apr. 1, 2020, as Appl. No. 16/837,618.
Claims priority of provisional application 62/828,186, filed on Apr. 2, 2019.
Prior Publication US 2020/0320228 A1, Oct. 8, 2020
Int. Cl. G06F 30/12 (2020.01); B29C 64/386 (2017.01); B33Y 50/00 (2015.01); G06T 11/20 (2006.01); G06T 17/30 (2006.01)
CPC G06F 30/12 (2020.01) [B29C 64/386 (2017.08); B33Y 50/00 (2014.12); G06T 17/30 (2013.01); G06T 11/203 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method comprising:
generating, by a computer aided design program, 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, by the computer aided design program, 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, by the computer aided design program, 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, by the computer aided design program, input to modify the control mesh of the subdivision surface model of the subdivision surface;
modifying, by the computer aided design program, the control mesh in accordance with the input to form a modified control mesh;
obtaining, by the computer aided design program, an updated limit surface from the modified control mesh;
finding, by the computer aided design program, 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, by the computer aided design program, the at least one modified NURBS surface in the stored NURBS surfaces with the replacement NURBS surface;
applying, by the computer aided design program, 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, by the computer aided design program, 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.