MODIFICATION OF A CONSTRAINED ASYMMETRICAL SUBDIVISION MESH

• US 20170177770A1
• Filed: 08/16/2016
• Published: 06/22/2017
• Est. Priority Date: 12/16/2015
• Status: Active Application

• Current Assignee: Dassault Systemes SA
• Original Assignee: Dassault Systemes SA
• Inventors: Letzelter, Frederic, Chauvet, Jean-Marc, Dufau, Christophe
• Granted Patent: US 10,289,771 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 30/23 using finite element methods [FEM] or finite difference methods [FDM]

Abstract

Embodiments provide methods and systems for modifying a finite element mesh representation of a three-dimensional model. A method according to an embodiment defines a symmetric constraint of a finite element mesh where the finite element mesh is a representation of a subject 3D model and the symmetric constraint comprises two asymmetric zones of the finite element mesh to be modified symmetrically. Next, corresponding finite elements between the two asymmetric zones are identified and a manipulation to at least one of the identified corresponding finite elements is performed. In response, the manipulation is performed symmetrically on a second or more of the identified corresponding finite elements where the second or more finite elements were identified as corresponding to the at least one finite element. In such an embodiment, performing the manipulation symmetrically results in the two asymmetric zones being modified symmetrically and represents a symmetrical modification in the subject 3D model.

Claims

1. A method of modifying a finite element mesh representation of a 3D model, the method comprising:

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

identifying corresponding finite elements between the two asymmetric zones;

the user performing a manipulation to at least one of the identified corresponding finite elements of the two asymmetric zones; and

performing the manipulation symmetrically 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 manipulation symmetrically results in the two asymmetric zones of the finite element mesh being modified symmetrically thereby representing a symmetrical modification in the subject 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 manipulation symmetrically 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 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 3D model, 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, the finite element mesh being a representation of a subject 3D model, and the symmetric constraint including two asymmetric zones of the finite element mesh to be modified symmetrically;

identify corresponding finite elements between the two asymmetric zones;

implement the user performing a manipulation to at least one of the identified corresponding finite elements of the two asymmetric zones; and

perform the manipulation symmetrically 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 manipulation symmetrically results in the two asymmetric zones of the finite element mesh being modified symmetrically thereby representing a symmetrical modification in the subject 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 manipulation symmetrically, 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 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 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:

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

identifying corresponding finite elements between the two asymmetric zones;

the user performing a manipulation to at least one of the identified corresponding finite elements of the two asymmetric zones; and

performing the manipulation symmetrically 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 manipulation symmetrically results in the two asymmetric zones of the finite element mesh being modified symmetrically thereby representing a symmetrical modification in the subject 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.