Method for cell selection during feature generation in a computer-implemented solid modeling system

• US 6,654,654 B1
• Filed: 04/27/2000
• Issued: 11/25/2003
• Est. Priority Date: 04/27/2000
• Status: Active Grant

• Current Assignee: Autodesk, Inc.
• Original Assignee: Autodesk, Inc.
• Inventors: Subrahmanyam, Somashekar Ramachandran, Jayasuriya, Mahabaduge Janaka Kithsiri
• Primary Examiner(s): Picard, Leo
• Assistant Examiner(s): Garland, Steven R.
• Application Number:
  US09/561,377
• Time in Patent Office: 1,307 Days
• Field of Search: 700/97, 700/98, 700/182, 700/86, 700/183, 345/418-420, 345/442, 345/441, 345/619, 345/629, 345/630, 703/1
• US Class Current: 700/98
• CPC Class Codes: G06F 30/00 Computer-aided design [CAD]
• CPC Class Codes: G06T 17/10 Constructive solid geometry [CSG] using solid primitives, e.g. cylinders, cubes
• CPC Class Codes: G06T 19/20 Editing of 3D images, e.g. changing shapes or colours, aligning objects or positioning parts
• CPC Class Codes: G06T 2219/2021 Shape modification

Abstract

A computer-implemented solid modeling system that generates Rib and Web features. One or more attribute values are set to indicate whether extended start and end segments for each chain of an open profile modeled in the system intersect with a part modeled in the system. The open profile and a sheet with attributes and their specified behaviors are inserted into the tool. The tool, which is generated from the open profile is united with the part to create a cellular topology graph structure, wherein the attributes get propagated to one or more cells of the cellular topology graph structure. The Rib or Web feature is then generated from one or more cells selected from the cellular topology graph structure based on the propagated attribute values.

Claims

1. A method for generating a feature in a computer-implemented solid modeling system, comprising:

(a) setting one or more attribute values to indicate whether extended start and end segments for each chain of an open profile intersect with a part modeled in the system;

(b) inserting the open profile and sheet with attributes into a tool;

(c) uniting the tool with the inserted open profile and sheet with the part to create a cellular topology graph structure, wherein the attributes get propagated to the cellular topology graph structure; and

(d) generating the feature from one or more cells selected from the cellular topology graph structure based on the propagated attributes.

2. The method of claim 1, wherein the feature is selected from a group comprising a rib feature and a web feature.

3. The method of claim 1, wherein the setting step further comprises:

constructing a ray tangential to the start segment;

determining whether the ray intersects with the part; and

setting an attribute value associated with a vertex connecting the start segment and the ray based on whether the ray intersects with the part.

4. The method of claim 1, wherein the setting step further comprises:

constructing a ray tangential to the end segment;

determining whether the ray intersects with the part; and

setting an attribute value associated with a vertex connecting the end segment and the ray based on whether the ray intersects with the part.

5. The method of claim 1, wherein the uniting step further comprises:

inserting the profile and the sheet with the attributes into the tool; and

uniting the tool with the part in a non-regularized manner to create the cellular topology graph structure.

6. The method of claim 1, wherein the generating step further comprises:

identifying valid cells within the cellular topology graph structure based on the propagated attributes, and generating the feature from the valid cells.

7. The method of claim 1, wherein the open profile is created without the start and end segments aligned with the part.

8. The method of claim 1, wherein the profile is extruded in a perpendicular direction to the plane of the profile to create the tool.

9. The method of claim 1, wherein the tool and the part are united to create a rib feature.

10. The method of claim 1, wherein the tool and the part are unioned, subtracted or intersected to create a web feature.

11. The method of claim 1, wherein the solid modeling system decides what cells are retained to create the feature from a given set of part-type, tool-type and common type cells.

12. The method of claim 11, wherein a cell is one of the valid cells if one or more of its edges or faces includes at least a portion of the profile, and the vertices of the start and end segments do not include attributes or the start and end segments have attributes with set values.

13. The method of claim 11, wherein all the part-type cells and the valid tool-type cells are kept for a rib feature.

14. The method of claim 11, wherein the part-type cells are kept for a web feature based on an operation type.

15. The method of claim 14, wherein all the part-type cells and the valid tool-type cells are kept for a union operation.

16. The method of claim 14, wherein all the part-type cells except those that are the valid tool-type cells are kept for a cut operation.

17. The method of claim 14, wherein only the valid tool-type cells that are also part-type cells are kept for an intersect operation.

18. A computer-implemented graphics system, comprising:

(a) a computer; and

(b) a feature-based modeler, executed by the computer, having logic for;

(1) setting one or more attribute values to indicate whether extended start and end segments for each chain of an open profile intersect with a part modeled in the system;

(2) inserting the open profile and sheet with attributes into the tool;

(3) uniting the tool with the inserted open profile and sheet with the part to create a cellular topology graph structure, wherein the attributes get propagated to the cellular topology graph structure; and

(4) generating the feature from one or more cells selected from the cellular topology graph structure based on the propagated attributes.

19. The system of claim 18, wherein the feature is selected from a group comprising a rib feature and a web feature.

20. The system of claim 18, wherein the logic for setting further comprises logic for:

constructing a ray tangential to the start segment;

determining whether the ray intersects with the part; and

setting an attribute value associated with a vertex connecting the start segment and the ray based on whether the ray intersects with the part.

21. The system of claim 18, wherein the logic for setting further comprises logic for:

constructing a ray tangential to the end segment;

determining whether the ray intersects with the part; and

setting an attribute value associated with a vertex connecting the end segment and the ray based on whether the ray intersects with the part.

22. The system of claim 18, wherein the logic for uniting further comprises logic for:

inserting the profile and the sheet with the attributes into the tool; and

uniting the tool with the part in a non-regularized manner to create the cellular topology graph structure.

23. The system of claim 18, wherein the logic for generating further comprises logic for:

identifying valid cells within the cellular topology graph structure based on the propagated attributes; and

generating the feature from the valid cells.

24. The system of claim 18, wherein the profile is created without the start and end segments aligned with the part.

25. The system of claim 18, wherein the profile is extruded in a perpendicular direction to the plane of the profile to create the tool.

26. The system of claim 18, wherein the tool and the part are united to create a rib feature.

27. The system of claim 18, wherein the tool and the part are unioned, subtracted or intersected to create a web feature.

28. The system of claim 27, wherein the solid modeling system decides what cells are retained to create the feature from a given set of part-type, tool-type and common type cells.

29. The system of claim 28, wherein a cell is one of the valid cells if one or more of its edges or faces includes at least a portion of the profile, and the vertices of the start and end segments do not include attributes or the start and end segments have attributes with set values.

30. The system of claim 28, wherein all the part-type cells and the valid tool-type cells are kept for a rib feature.

31. The system of claim 28, wherein the part-type cells are kept for a web feature based on an operation type.

32. The system of claim 31, wherein all the part-type cells and the valid tool-type cells are kept for a union operation.

33. The system of claim 31, wherein all the part-type cells except those that are the valid tool-type cells are kept for a cut operation.

34. The system of claim 31, wherein only the valid tool-type cells that are also part-type cells are kept for an intersect operation.

35. An article of manufacture embodying logic for generating a feature in a computer-implemented solid modeling system, the logic comprising:

(a) setting one or more attribute values to indicate whether extended start and end segments for each chain of an open profile intersect with a part modeled in the system;

(b) inserting the open profile and sheet with attributes into the tool;

(c) uniting the tool with the inserted open profile and sheet with the part to create a cellular topology graph structure, wherein the attributes get propagated to the cellular topology graph structure; and

(d) generating the feature from one or more cells selected from the cellular topology graph structure based on the propagated attributes.

36. The article of manufacture of claim 35, wherein the feature is selected from a group comprising a rib feature and a web feature.

37. The article of manufacture of claim 35, wherein the logic for setting further comprises logic for:

constructing a ray tangential to the start segment;

determining whether the ray intersects with the part; and

setting an attribute value associated with a vertex connecting the start segment and the ray based on whether the ray intersects with the part.

38. The article of manufacture of claim 35, wherein the logic for setting further comprises logic for

constructing a ray tangential to the end segment;

determining whether the ray intersects with the part; and

setting an attribute value associated with a vertex connecting the end segment and the ray based on whether the ray intersects with the part.

39. The article of manufacture of claim 35, wherein the logic for uniting further comprises logic for:

inserting the profile and the sheet with the attributes into the tool; and

uniting the tool with the part in a non-regularized manner to create the cellular topology graph structure.

40. The article of manufacture of claim 35, wherein the logic for generating further comprises logic for:

identifying valid cells within the cellular topology graph structure based on the propagated attributes; and

generating the feature from the valid cells.

41. The article of manufacture of claim 35, wherein the profile is created without the start and end segments aligned with the part.

42. The article of manufacture of claim 35, wherein the profile is extruded in a perpendicular direction to the plane of the closed profile to create the tool.

43. The article of manufacture of claim 35, wherein the tool and the part are united to create a rib feature.

44. The article of manufacture of claim 35, wherein the tool and the part are unioned, subtracted or intersected to create a web feature.

45. The article of manufacture of claim 35, wherein the solid modeling system decides what cells are retained to create the feature from a given set of part-type, tool-type and common type cells.

46. The article of manufacture of claim 45, wherein a cell is one of the valid cells if one or more of its edges or faces includes at least a portion of the profile, and the vertices of the start and end segments do not include attributes or the start and end segments have attributes with set values.

47. The article of manufacture of claim 45, wherein all the part-type cells and the valid tool-type cells are kept for a rib feature.

48. The article of manufacture of claim 45, wherein the part-type cells are kept for a web feature based on an operation type.

49. The article of manufacture of claim 48, wherein all the part-type cells and the valid tool-type cells are kept for a union operation.

50. The article of manufacture of claim 48, wherein all the part-type cells except those that are the valid tool-type cells are kept for a cut operation.

51. The article of manufacture of claim 48, wherein only the valid tool-type cells that are also part-type cells are kept for an intersect operation.