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Penalty-Function Coloring in the Editing of Set-Theoretic Models

IP.com Disclosure Number: IPCOM000101082D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Woodwark, JR: AUTHOR

Abstract

A technique in computer graphics and solid modelling is disclosed in which coloring derived from penalty function of the primitive to be edited is used. It allows a preview of the result of editing a set-theoretic model.

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Penalty-Function Coloring in the Editing of Set-Theoretic Models

       A technique in computer graphics and solid modelling is
disclosed in which coloring derived from penalty function of the
primitive to be edited is used.  It allows a preview of the result of
editing a set-theoretic model.

      How the active zone could be used to indicate the scope of an
edit to a set-theoretic (CSG) solid model is shown in (*).  That
technique is a good initial approach to an important problem, but it
is not a perfect solution.  An example of a difficulty is shown in
Fig. 1.  All of the model except for the cylinder is in the active
zone of the cylinder and can be modified by moving the cylinder. What
is needed is to know whether moving the cylindrical primitive
leftwards will cut the overhanging lip, which, in this case, is
dependent solely on the length of the cylinder.  The most obvious way
to see whether this will occur is to generate a new picture of a
model in which the 'sign' of the cylinder is changed and it appears
as a 'solid', but there is considerable potential confusion in this
approach.

      In the second example shown in Fig. 2, a more serious problem
of the same sort is shown.  In this case, moving the positive
cylindrical primitive may or may not cause it to alter the shape of
the slot (marked *), depending on the cylinder's hidden length inside
the object.  In this case, it is not at all clear that changing the
signs of any primitives would pro...