Abstract
In casting, molten material is poured into the cavity of the cast and allowed to solidify. The cast has two main parts to be removed in opposite parting directions. To manufacture more complicated objects, the cast may also have a side core to be removed in a direction skewed to the parting directions. In this paper, given an object and the parting and side core directions, we give necessary and sufficient conditions to verify whether a cast can be constructed for these directions. In the case of polyhedral objects, we develop a discrete algorithm to perform the test in O(n 3log n) time, where n is the object size. If the test result is positive, a cast with complexity O(n 3) can be constructed within the same time bound. We also present an example to show that a cast may have Θ(n 3) complexity in the worst case. Thus, the complexity of our cast is worst-case optimal.
Work by Ahn, Bae and Chwa was supported by the Brain Korea 21 Project, The School of Information Technology, KAIST, in 2005. Work by Cheng was supported by Research Grant Council, Hong Kong, China (DAG04/05.EG21).
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© 2005 Springer-Verlag Berlin Heidelberg
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Ahn, HK., Bae, S.W., Cheng, SW., Chwa, KY. (2005). Casting an Object with a Core. In: Deng, X., Du, DZ. (eds) Algorithms and Computation. ISAAC 2005. Lecture Notes in Computer Science, vol 3827. Springer, Berlin, Heidelberg. https://doi.org/10.1007/11602613_6
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DOI: https://doi.org/10.1007/11602613_6
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-30935-2
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