Microsoft KB Archive/150113

= Microsoft Knowledge Base =

BUG: Hidden Line in Tools Module Cannot Render a Simple Sphere
Last reviewed: April 26, 1996

Article ID: Q150113

The information in this article applies to:


 * Softimage 3D for Windows NT, versions 3.0 and 3.01
 * Softimage 3D for IRIX, version 3.0

SYMPTOMS
Hidden Line in the Softimage 3D Tools module cannot render a simple sphere in which a few points have been moved even when all the following checks are performed:


 * Normals are checked.
 * The sphere is randomized with a 0, 0, 0 setting.
 * Normals are recomputed.
 * The sphere is converted to polygons or NURBS.

An error message such as the following one appears in the Status box:

WARNING: Collision of polygons: a & b, that have the same oriented edge (c, d) NOTE: The same error message appears when converting the sphere into a polygon mesh.

RESOLUTION
Use either of the following two workarounds:

 Instead of using Hidden Line, use NURBS for the entire process. -or-  Cap the sphere as follows: In the Information menu, select Selection, and verify that the cappings are activated at both ends of the sphere: Top and Bottom. Hidden Line can render without difficulty when the sphere is capped at its poles (poles are the Top and Bottom of the sphere). Hidden Line cannot render when the points moved are near the poles of the sphere. When points are moved near the poles of the sphere, the poles of the sphere are destabilized, which causes a problem in the triangle structuring of the Hidden Line process. However, if points are moved in the middle of the sphere, Hidden Line can render without difficulty. 

STATUS
Softimage has confirmed this to be a bug in the Softimage products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

NOTE: Softimage Inc. is a wholly owned subsidiary of Microsoft Corporation.