Tolerance Variables

List of:	Discussion Topic
Subjects:	Precision and Tolerance
Contents:	Fundamental Concepts

In order to maintain model integrity, the modeler must work to specified tolerances. Applying tolerances insures proper interpretation of positions, such as maintaining that the points of vertices lie on the curves of the edges they bound or correctly determining if a position is inside or outside a volume.

ACIS uses the tolerance variables SPAresabs, SPAresnor, and SPAresfit to control modeling operations. These are global variables defined in the system that affect modeling functionality. All modeling operations in ACIS use these tolerance variables to maintain consistency of mathematical operations. Although SPAresnor should not be changed by the application, SPAresabs and SPAresfit may be changed, with great care, as explained in this chapter.

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