EP0361787A2
Expired / Lapsed
EP
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A boundary representation solid modelling system
Assignee: International Business Machines Corp
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Filing: 1989-09-21
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Granted: —
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Expires: 2009-09-21
Abstract
Abstract A boundary representation solid modelling system is described that enables building of a solid-model through a trial-and-error approach. The result of a non-manifold union set operation on a geometric model is used to update a non-manifold boundary representation date file. Correspondence between elements in the boundary representation file and primitives is retained in another store. This allows elements of a non-manifold boundary representation, originating from a primitive, to be identified when the primitive is specified, and vice-versa. A history of set operations is also stored. Reworking of a set operation is achieved by selecting a primitive to delete, accessing and deleting corresponding elements from the boundary representation file and modifying the set operation history file. The invention thus enables cancellation of reworking of a set operation independently of its order. Hence, or a set operation executed at any given time can be rapidly reworked.
Inventors
- 👤 Shinji Kawabe
- 👤 Hiroshi Masuda
- 👤 Kenji Shimada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 02:52
CPC Classifications
G; G06; G06T; G06T17/00; G06T17/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
151 words
A boundary representation solid modelling system comprising: (a) means for specifying a kind of set operations and inputting a geometric model, (b) means for executing a non-manifold union set operation and updating a non-manifold boundary representation data file with a result of the operation, each time a geometric model is input, (c) means for updating element correspondence data file which describes correspondence between an element of the boundary representation and an input geometric model, (d) means for updating a set operation history data file by adding data on the specified kind of set operations and the input geometric model, (e) means for referring to the set operation history data file and marking elements in the non-manifold boundary representation to be output as a result of the set operation, and (f) storage means for storing the boundary representation data file, the element correspondence data file, and the set operation history data file.
Claim 2
Dependent Claim
151 words
A boundary representation solid modelling system comprising: (a) means for specifying a kind of set operations and inputting a geometric model, (b) means for executing a non-manifold union set operation and updating a non-manifold boundary representation data file with a result of the operation, each time a geometric model is input, (c) means for updating element correspondence data file which describes correspondence between an element of the boundary representation and an input geometric model, (d) means for updating a set operation history data file by adding data on the specified kind of set operations and the input geometric model, (e) means for referring to the set operation history data file and marking elements in the non-manifold boundary representation to be output as a result of the set operation, and (f) storage means for storing the boundary representation data file, the element correspondence data file, and the set operation history data file.
Claim 3
Dependent Claim
155 words
A boundary representation solid modelling system as set forth in Claim 1, further comprising: (g) means for specifying a geometric model to be deleted, (h) means for deleting element correspondence data associated with a specified geometric model from the element correspondence data file, each time a geometric model to be deleted is specified, (i) means for modifying the non-manifold boundary representation by deleting data on elements from the boundary representation data file, which elements have lost correspondence with any geometric model as a result of the deletion of the element correspondence data by the said means (h), (j) means for updating the set operation history data file by deleting data on the deleted geometric model and the kind of set operations therefor, and (k) means for referring to the set operation history data file and marking elements in the non-manifold boundary representation to be output as a result of the deletion of the geometric model.
Claim 4
Dependent Claim
47 words
A boundary representation solid modelling system as set forth in Claim 1 or 2, further comprising: (1) output means for extracting data on the elements to be output from the non-manifold boundary representation data file in accordance with the marking result by said means (e) or (k).
Claim 5
Dependent Claim
38 words
A boundary representation solid modelling system as set forth in any one of Claims 1 to 3, wherein elements of the non-manifold boundary representation are a point, an edge, a face and a closed space surrounded by faces.
Claim 6
Dependent Claim
51 words
A solid modelling system as set forth in any one of Claims 1 to 4, wherein the non-manifold boundary representation data file contains: (i) geometric data of the elements, (ii) topological data of the elements, and (iii) data indicating whether or not the elements belong to a subset to be output.
Claim 7
Dependent Claim
20 words
A solid modelling system as set forth in Claim 5, wherein said means (b) updates said data (i) and (ii).
Claim 8
Dependent Claim
47 words
A solid modelling system as set forth in Claim 5, wherein said means (e) determines a subset of elements in the non-manifold boundary representation to be output by referring to a history data file of the set operations, and updates said data (iii) based on the result.
References Cited (Backward Citations)
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