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Proceedings Paper

Solid modeling in GEMS 4.0
Author(s): Changgui Yang; Yujian Chen; Gang Fan; Jiaguang Sun
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Paper Abstract

A product modeling system GEMS 4.0 has been implemented, in which feature representation is used at the highest level abstraction of a product model, boundary representation is used at the bottom level, while CSG model is adopted at the median level. A BRep data structure capable of modeling non-manifold is adopted. NURBS representation is used for all curved surfaces. Quadric surfaces have dual representations consisting of their geometric data such as radius, centerpoint, and center axis. The geometric data are not only necessary for the mapping of form features of the corresponding CSG models, but also useful for accelerating certain time consuming calculations such as surface-surface intersections. Boundary representation of free form surfaces are easily built by sweeping and skinning method with NURBS geometry. Set operations on curved solids with boundary representation are performed by an evaluation process consisting of four steps: intersection, construction, classification and selection.

Paper Details

Date Published: 22 March 1996
PDF: 8 pages
Proc. SPIE 2644, Fourth International Conference on Computer-Aided Design and Computer Graphics, (22 March 1996); doi: 10.1117/12.235574
Show Author Affiliations
Changgui Yang, Tsinghua Univ. (China)
Yujian Chen, Tsinghua Univ. (China)
Gang Fan, Tsinghua Univ. (China)
Jiaguang Sun, Tsinghua Univ. (China)


Published in SPIE Proceedings Vol. 2644:
Fourth International Conference on Computer-Aided Design and Computer Graphics
Shuzi Yang; Ji Zhou; Cheng-Gang Li, Editor(s)

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