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Article
Fleshing Out Projections
IBM Journal of Research and Development
  • Michael A. Wesley
  • George Markowsky, Missouri University of Science and Technology
Abstract

In an earlier paper, the authors presented an algorithm for finding all polyhedral solid objects with a given set of vertices and straight line edges (its wire frame). This paper extends the Wire Frame algorithm to find all solid polyhedral objects with a given set of two dimensional projections. These projections may contain depth information in the form of dashed and solid lines, may represent cross sections, and may be overall or detail views. The choice of labeling conventions in the projections determines the difficulty of the problem. It is shown that with certain conventions and projections the problem of fleshing out projections essentially reduces to the problem of fleshing out wire frames. Even if no labeling is used, the Projections algorithm presented here finds all solutions even though it is possible to construct simple examples with a very large number of solutions. Such examples have a large amount of symmetry and various accidental coincidences which typically do not occur in objects of practical interest. Because of its generality, the algorithm can handle pathological cases if they arise. This Projections algorithm, which has applications in the conversion of engineering drawings in a Computer Aided Design, Computer Aided Manufacturing (CADCAM) system, has been implemented. The algorithm has successfully found solutions to problems that are rather complex in terms of either the number of possible solutions or the inherent complexity of projections of objects of engineering interest.

Department(s)
Computer Science
Keywords and Phrases
  • Computer Graphics
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 1981 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.
Publication Date
11-1-1981
Publication Date
01 Nov 1981
Disciplines
Citation Information
Michael A. Wesley and George Markowsky. "Fleshing Out Projections" IBM Journal of Research and Development Vol. 25 Iss. 6 (1981) p. 934 - 954 ISSN: 0018-8646
Available at: http://works.bepress.com/george-markowsky/32/