EP0364243A2
Expired / Lapsed
EP
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Three-dimensional geometry processing method and apparatus therefor
Assignee: Panasonic Holdings Corp
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Filing: 1989-10-11
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Granted: —
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Expires: 2009-10-11
Abstract
Abstract Devised is a novel data structure which is termed as "Boundary representation by means of triangle" that can dispense with sharing of edges when modelling three-dimensional geometry. As a result, it is now possible for engineers to execute geometry processing operation including geometrical set operation, computation of mass property, and hidden-surface/line removal process merely by applying very simple algorithm based on triangular face data. The invented art has proved to be capable of executing geometry processing operation at a speed much faster than the conventional "B-Rep" processing means. Furthermore, since there is no need of sharing edges, the volume of triangular face data has sharply been decreased. To materialize the invented art, only a very simple apparatus is needed, which is merely composed of geometry processing unit 10, triangular face data memory 13, vertex data memory 14, and edge data memory 15.
Inventors
- 👤 Yoshiki Arakawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 21:12
CPC Classifications
G; G06; G06T; G06T1/00; G06T15/00; G06T15/10; G06T15/40; G06T17/00; G06T17/10; G09; G09B; G09B9/00; G09B9/02; G09B9/08; G09B9/30; G09B9/301
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
44 words
(1) A method for three-dimensional geometry processing being characterized in that when an arbitrary three-dimensional geometry is modeled, the surface of the geometry is expressed and processed by using sets of "triangular faces sharing its edge(s) with others" and "triangular faces sharing no edges".
Claim 2
Dependent Claim
69 words
(2) A method for three-dimensional geometry processing being characterized in that when geometrical set operations such as union, subtraction, intersection, etc. are carried out among the geometry, the interference relations among the triangular faces composing each geometry are defined and further operations can be performed by subdividing the triangle into smaller ones if it has an intersection or the plurality of them, obtaining an accurate geometry as the result.
Claim 3
Dependent Claim
57 words
(3) A method for three-dimensional geometry processing being characterized in that in calculating mass properties such as volume, the center of gravity, moment of inertia, etc. of a three-dimensional geometry, three-dimensional run length data are transduced from the triangular face data expressing the geometry and the calculations for the mass properties are performed by using the data.
Claim 4
Dependent Claim
55 words
(4) A method for three-dimensional geometry processing being characterised in that in hidden line removal and displaying a three-dimensional geometry, edge lines are found from the triangles expressing the three-dimensional geometry and by judging the depth between the edge lines and the triangles, the hidden line removal processing can be carried out, displaying the geometry.
Claim 5
Dependent Claim
70 words
(5) A three-dimensional geometry processing apparatus comprising a triangular face data storage unit processing the triangular face data consisting of the surface of a three-dimensional geometry, a vertex data storage unit storing the vertex data of said triangular face data, an edge data storage unit storing the edge data of said triangular data and a geometry processing operation unit performing various operations including geometrical set operation, mass properties calculation, etc.
Claim 6
Dependent Claim
43 words
(6) The three-dimensional geometry processing apparatus as defined in claim 5 comprising a geometry processing operation unit wherein the surface of a three-dimensional geometry is divided into "triangular faces sharing its edge(s) with others" and "those sharing no edges" by its processing unit.
Claim 7
Dependent Claim
72 words
(7) The three-dimensional geometry processing apparatus as defined in claim 5 comprising a geometry processing operation unit wherein when geometry set operations are performed among geometry the interference relations among the triangles expressing the surface of each three- dimensional geometry is judged and further operations can be performed by subdividing the triangle into smaller ones if it has an intersection or the plurality of them, obtaining an accurate shape as the result.
Claim 8
Dependent Claim
52 words
(8) The three-dimensional geometry processing appara tus as defined in claim 5 comprising a geometry processing operation unit which has a function wherein three-dimensional run-length data are transduced from the triangular face data expressing the surface of a three-dimensional geometry and by using the data, calculation of mass properties can be performed.
Claim 9
Dependent Claim
62 words
(9) The three-dimensional geometry processing apparatus as defined in claim 5 comprising a geometry processing operation unit in which in hidden line removal and displaying a three-dimensional geometry, edges are found from the triangular faces expressing the three-dimensional geometry and by the judgement of the depth among these edges and the triangular faces, the hidden line removal is performed, displaying the geometry.
Claim 10
Dependent Claim
105 words
(10) A three-dimensional geometry processing apparatus comprising a triangular face data storage unit to store the triangular face data consisting of the surface of a three-dimensional geometry, a vertex data storage unit to store the vertex data of said triangular faces, an edge data storage unit to store the edge data, a geometry processing operation unit which performs various operations such as geometrical set operation, mass properties calculation, etc., a frame memory unit to store video picture data, a raster-type display unit and a unit which displays pictures on the said display unit in respect to said video picture data from said frame memory unit.
References Cited (Backward Citations)
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