Title: | Coherence in scan-line algorithms for CSG |
Authors: | Gröller, Eduard Brunner, Peter |
Citation: | Journal of WSCG. 1994, vol. 2, no. 1-2, p. 55-65. |
Issue Date: | 1994 |
Publisher: | Václav Skala - UNION Agency |
Document type: | článek article |
URI: | http://wscg.zcu.cz/wscg1994/wscg94.htm http://hdl.handle.net/11025/16065 |
ISSN: | 1213-6972 (print) 1213-6980 (CD-ROM) 1213-6964 (online) |
Keywords: | CSG;kvadriky;čtecí linka algoritmu;rozšířený BRep;zaoblené hrany |
Keywords in different language: | CSG;quadrics;scan line algorithm;extended BRep;curved edges |
Abstract in different language: | Scan-line algorithms for visibility calculation exploit various types of coherence properties. Several scan-line algorithms for Constructive Solid Geometry (CSG) are discussed. In one approach CSG primitives are represented by polygonal approximations. Another technique processes CSG primitives as general quadric surfaces. We investigate the handling of frequently occuring quadric surfaces (cube, cone, sphere, cylinder)as distinct cases. Thus the differing properties of such objects can be used more efficiently than a uniform approach would allow. A so called eBRep (extended Boundary Representation) is defined for the frequently occuring quadric surfaces. An eBRep is an exact representation of a quadric object and contains curved edges and faces. For each of the above mentioned quadric surfaces a different, geometry dependent eBRep is specified. A comparison between the polygon-based scan-line algorithm for CSG and our eBRep based approach is done. eBRep is a storage efficient exact representation of quadric surfaces, well suited for scan-line visibility determination. |
Rights: | © Václav Skala - UNION Agency |
Appears in Collections: | Volume 2, number 1-2 (1994) |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
Groeller_94.pdf | Plný text | 1,25 MB | Adobe PDF | View/Open |
Please use this identifier to cite or link to this item:
http://hdl.handle.net/11025/16065
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