Microsoft KB Archive/153879

= Microsoft Knowledge Base =

Normals May Be Inversed When Curves are Drawn Clockwise
Last reviewed: September 3, 1996

Article ID: Q153879

The information in this article applies to:


 * Softimage 3D for IRIX, version 3.50

SUMMARY
When performing either Surface->Extrusion or Surface->Revolution in the Softimage 3D Model module, draw all the curves counter-clockwise; otherwise, the normals in the resulting model might be inversed. Inversed normals cause Softimage 3D to read the model inside out, which means the light source is perceived to be on the inside of the model, and the model does not show up in either the Perspective window, the Shade preview, or the Softimage 3D Matter module Preview.

If, for this or any other reason, your model's normals are inversed, use the Effect->Inverse function in the Model module to reorient them to the surface of the model.