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NOTE: This Technical Q&A has been retired. Please see the Technical Q&As page for current documentation.

Default Surface/Shader UV Params For Caps of Cones & Cylinders

Q: Does anyone know what the default surface/shader UV parameterizations are for the caps of cones and cylinders in QuickDraw 3D version 1.5?

A: Check out the article titled, "New QuickDraw 3D Geometries", by Philip J. Schneider in develop journal issue 28. Look for the section "Ellipsoids, Cones, Cylinders, and Tori", where you'll find a discussion about the default UV parameterization of these primitives. Here's a relevant excerpt from the article: "For the cone and cylinder, the parametric origin is on the bottom edge, at the point where the majorRadius vector ends. V goes up while U goes around in the direction shown by the arrows. The bottom of the cone, and the top and bottom of the cylinder, are parameterized exactly like the disk."

The discussion about the disk primitive is in the article as well.

[Jul 11 1997]

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