Modification of a constrained asymmetrical subdivision mesh

1. A method of modifying a finite element mesh representation of a computer aided design (CAD) 3D model representing a real-world object, the method comprising:

by a user, defining a symmetric constraint of a finite element mesh using a graphical user interface coupled to a processor, the finite element mesh being a representation of a subject CAD 3D model including a shape of the subject CAD 3D model, and the symmetric constraint including two asymmetric zones of the finite element mesh to be modified symmetrically;

automatically identifying, by the processor, corresponding finite elements between the two asymmetric zones;

performing by the user, user-interactively through the graphical user interface, modification to shape of the finite element mesh through a manipulation to at least one of the identified corresponding finite elements of the two asymmetric zones; and

performing automatically by the processor a symmetrical manipulation on a second or more of the identified corresponding finite elements, the second or more finite elements identified as corresponding to the at least one finite element, wherein performing the symmetrical manipulation results in the two asymmetric zones of the finite element mesh being modified symmetrically thereby representing a symmetrical modification to the shape of the subject CAD 3D model.

2. The method of claim 1 wherein identifying corresponding finite elements between the two asymmetric zones comprises:

identifying symmetric edges, vertices, and faces of the two zones.

3. The method of claim 1 wherein performing the symmetrical manipulation comprises:

determining a local symmetric plane defined by a barycenter of the at least one finite element and the second or more finite elements and normal to a direction defined by the at least one finite element and the second or more finite elements;

computing a symmetric transformation of the manipulation performed by the user using the local symmetric plane; and

performing the computed symmetric transformation on the second or more finite elements.

4. The method of claim 1 wherein the symmetric constraint applies only to a subpart of the finite element mesh.

5. The method of claim 1 wherein defining a symmetric constraint comprises at least one of:

identifying a first group of connected faces and a second group of connected faces;

identifying a plane and a group of connected faces;

identifying a group of faces; and

identifying a plane.

6. The method of claim 1 wherein elements of the two asymmetric zones of the finite element mesh are identified with respective unique tags.

7. The method of claim 1 wherein defining the symmetric constraint comprises:

determining a separating shape between the two asymmetric zones.

8. The method of claim 7 wherein the separating shape is a plane.

9. The method of claim 7 wherein the separating shape is used in identifying the corresponding finite elements between the two asymmetric zones.

10. A computer system for modifying a finite element mesh representation of a computer aided design (CAD) 3D model representing a real-world object, the computer system comprising:

a processor; and

a memory with computer code instructions stored thereon, the processor and the memory, with the computer code instructions being configured to cause the system to:

implement, by a user, defining a symmetric constraint of a finite element mesh using a graphical user interface coupled to the processor, the finite element mesh being a representation of a subject CAD 3D model including a shape of the subject CAD 3D model, and the symmetric constraint including two asymmetric zones of the finite element mesh to be modified symmetrically;

automatically identify, by the processor, corresponding finite elements between the two asymmetric zones;

implement the user performing, user-interactively through the graphical user interface, modification to shape of the finite element mesh through a manipulation to at least one of the identified corresponding finite elements of the two asymmetric zones; and

perform automatically by the processor a symmetrical manipulation on a second or more of the identified corresponding finite elements, the second or more finite elements identified as corresponding to the at least one finite element, wherein performing the symmetrical manipulation results in the two asymmetric zones of the finite element mesh being modified symmetrically thereby representing a symmetrical modification to the shape of the subject CAD 3D model.

11. The system of claim 10 wherein, in identifying corresponding finite elements between the two asymmetric zones, the processor and the memory, with the computer code instructions, are further configured to cause the system to:

identify symmetric edges, vertices, and faces of the two zones.

12. The system of claim 10 wherein, in performing the symmetrical manipulation, the processor and the memory, with the computer code instructions, are further configured to cause the system to:

determine a local symmetric plane defined by a barycenter of the at least one finite element and the second or more finite elements and normal to a direction defined by the at least one finite element and the second or more finite elements;

compute a symmetric transformation of the manipulation performed by the user using the local symmetric plane; and

perform the computed symmetric transformation on the second or more finite elements.

13. The system of claim 10 wherein the symmetric constraint applies only to a subpart of the finite element mesh.

14. The system of claim 10 wherein, in defining a symmetric constraint, the processor and the memory, with the computer code instructions, are further configured to cause the system to perform at least one of:

identifying a first group of connected faces and a second group of connected faces;

identifying a plane and a group of connected faces;

identifying a group of faces; and

identifying a plane.

15. The system of claim 10 wherein elements of the two asymmetric zones of the finite element mesh are identified with respective unique tags.

16. The system of claim 10 wherein, in defining the symmetric constraint, the processor and the memory, with the computer code instructions, are further configured to cause the system to:

determine a separating shape between the two asymmetric zones.

17. The system of claim 16 wherein the separating shape is a plane.

18. The system of claim 16 wherein the separating shape is used in identifying the corresponding finite elements between the two asymmetric zones.

19. A computer program product for modifying a finite element mesh representation of a computer aided design (CAD) 3D model representing a real-world object, the computer program product comprising computer-readable instructions stored on a non-transitory computer readable medium responsive to execution by a computing device that causes the computing device to perform operations comprising:

implementing, by a user, defining a symmetric constraint of a finite element mesh using a graphical user interface coupled to a processor, the finite element mesh being a representation of a subject CAD 3D model including a shape of the subject CAD 3D model, and the symmetric constraint including two asymmetric zones of the finite element mesh to be modified symmetrically;

automatically identifying, by the processor, corresponding finite elements between the two asymmetric zones;

implementing the user performing, user-interactively through the graphical user interface, modification to shape of the finite element mesh through a manipulation to at least one of the identified corresponding finite elements of the two asymmetric zones; and

performing automatically by the processor a symmetrical manipulation on a second or more of the identified corresponding finite elements, the second or more finite elements identified as corresponding to the at least one finite element, wherein performing the symmetrical manipulation results in the two asymmetric zones of the finite element mesh being modified symmetrically thereby representing a symmetrical modification to the shape of the subject CAD 3D model.

20. The computer program product of claim 19 wherein identifying corresponding finite elements between the two asymmetric zones comprises:

identifying symmetric edges, vertices, and faces of the two zones.