Process for computer-aided geometry modeling

• US 5,859,786 A
• Filed: 03/14/1997
• Issued: 01/12/1999
• Est. Priority Date: 03/15/1996
• Status: Expired due to Fees

• Current Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Original Assignee: Daimler-Benz AG (Mercedes-Benz Group AG)
• Inventors: Klein, Rudiger
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): FREJD, RUSSELL WARREN
• Application Number:
  US08/818,118
• Time in Patent Office: 669 Days
• Field of Search: 364/578, 364/468.03, 364/468.04, 364/468.25, 345/418, 345/419, 345/420, 345/433, 345/440, 395/118, 395/119, 395/120, 395/133, 395/140
• US Class Current: 703/2
• CPC Class Codes: G06F 30/17 Mechanical parametric or variational design
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects

Abstract

A process and system for the computer-aided geometry modeling which makes possible a declarative, sequence-independent description of geometric shapes and geometric features and leads to an integrated modeling, which unites in itself geometric relationships and connects them with non-geometric information. To achieve this, the geometry-related information is represented in the form of a representation element, to which a density (ρ) is assigned in the form of a real number. The linking of individual representation elements is performed by a single commutative and associative linking operation. A volume level, a topology level, and a generic area and edge level located between these levels are provided as the description levels for the actually relevant information. A feature level, at which features are defined and at which a knowledge-based system can be used, is located above these description levels.

Claims

1. A process for the computer-aided geometry modeling of a workpiece, comprising the steps of:

providing an integrated, declarative, sequence-independent and logic-based representation of the volume, area, edge, point and topology-related information in the form of a representation element (Γ

), comprising individual basic volumes, to which a density (ρ

) is assigned in the form of a real number (positive, zero, negative);

performing a linking of individual representation elements (Γ

) by a commutative and associative linking operation; and

creating description levels for the actually relevant information, also in their mutual dependence, in the form of a

volume level as the basic level for the description of elementary structures, whose composition is permanently preset,

topology level as a representation of the overall geometry, and

a generic area level located between the volume level and the topology level, and a generic edge level likewise located there for establishing the relationship between the topological structures and the volumes generating them.

2. The process in accordance with claim 1, further comprising the step of:

creating an information unit level as a feature level located above the description levels, at which information unit level objects (features) are defined in terms of their volume, area, point and topology related information with their attributes as well as the relations and dependences existing between them in the description levels.

3. The process in accordance with claim 1, further comprising using a knowledge-based system, which utilizes the possibilities of a geometry and feature description.

4. The process in accordance with claim 1, further comprising providing in the topology level both between areas and edges and between edges and points a defines relation and a constrains relation as two different types of topological relations, said defines relation describing the topology, and said constrains relation expressing that an object influences the topology of another object without being influenced itself.

5. The process in accordance with claim 1, wherein geometric models are a priori classified topologically in their description.

6. The process in accordance with claim 1, further comprising introducing for the topology level a holds relation, which states whether a defined topological, generic or volume instance is present in a current geometric model.

7. The process in accordance with claim 1, wherein the overall geometry is represented for each total set of decisions, and a subset of decisions which has led to a particular relationship is represented in said overall geometry for every individual relationship with respect to the total set of decisions, so that parts of the geometry which are linked with these decisions can be identified at the time of a change in the decisions.

8. The process in accordance with claim 2, further comprising using a knowledge-based system, which utilizes the possibilities of a geometry and feature description.

9. The process in accordance with claim 2, further comprising providing in the topology level both between areas and edges and between edges and points a defines relation and a constrains relation as two different types of topological relations, said defines relation describing the topology, and said constrains relation expressing that an object influences the topology of another object without being influenced itself.

10. The process in accordance with claim 2, wherein geometric models are a priori classified topologically in their description.

11. A system for the computer-aided geometry modeling of a workpiece, comprising the steps of:

means for providing an integrated, declarative, sequence-independent and logic-based representation of the volume, area, edge, point and topology-related information in the form of a representation element (Γ

), comprising individual basic volumes, to which a density (ρ

) is assigned in the form of a real number (positive, zero, negative);

means for performing a linking of individual representation elements (Γ

) by a commutative and associative linking operation; and

means for creating description levels for the actually relevant information, also in their mutual dependence, in the form of a

volume level as the basic level for the description of elementary structures, whose composition is permanently preset,

topology level as a representation of the overall geometry, and a generic area level located between the volume level and the topology level,

and a generic edge level likewise located there for establishing the relationship between the topological structures and the volumes generating them.

12. The system in accordance with claim 11, further comprising:

means for creating an information unit level as a feature level located above the description levels, at which information unit level objects (features) are defined in terms of their volume, area, point and topology related information with their attributes as well as the relations and dependences existing between them in the description levels.

13. The system in accordance with claim 11, further comprising a knowledge-based system, which utilizes the possibilities of a geometry and feature description.

14. The process in accordance with claim 11, further comprising means for providing in the topology level both between areas and edges and between edges and points a defines relation and a constrains relation as two different types of topological relations, said defines relation describing the topology, and said constrains relation expressing that an object influences the topology of another object without being influenced itself.

15. The system in accordance with claim 11, wherein said means to create description levels classifies geometric models topologically in their description.

16. The system in accordance with claim 11, further comprising means for introducing for the topology level a holds relation, which states whether a defined topological, generic or volume instance is present in a current geometric model.

17. The system in accordance claims 11, wherein the overall geometry is represented for each total set of decisions, and a subset of decisions which has led to a particular relationship is represented in said overall geometry for every individual relationship with respect to the total set of decisions, so that parts of the geometry which are linked with these decisions can be identified at the time of a change in the decisions.