HOWTO: Maintain Constant Material Shading with Surface Shadows
  
PSS ID Number: Q184923
Article last modified on 04-30-1998
 
IRIX:3.7,3.71; WINNT:3.7,3.71
 
IRIX winnt
 

======================================================================
---------------------------------------------------------------------
The information in this article applies to:
 
 - SOFTIMAGE 3D for IRIX, versions 3.7, 3.71
 - SOFTIMAGE 3D for Windows NT, versions 3.7, 3.71
---------------------------------------------------------------------
 
SUMMARY
=======
 
This article provides a method for creating shadows on a surface while
maintaining constant material shading. Use this method for scenes that
contain luminescent surfaces that must retain Specular, Ambient, and
Diffuse properties.
 
MORE INFORMATION
================
 
Follow these steps to render the scene twice using different surface
properties:
 
1. For your first layer (layer1), set the surface's Material Shading to
   Constant.
 
2. Hide all the scene objects except for the Lights (do not raytrace the
   lights).
 
3. Render layer1.
 
4. For the second layer (layer2), display (unhide) all the objects in the
   scene.
 
5. Set the surface's Material Shading back to its original Shading type
   (that is, Lambert, Phong, or Blinn).
 
6. Apply the Shadow_Matte Material Shader to the surface's Material
   (include the raytraced Lights in the Shadow_Matte's Light list).
 
7. Re-activate the raytraced Lights (lights that cast shadows).
 
8. Render layer2.
 
9. Composite layer2 (with Alpha) over layer1 (Opaque).
 
You will see shadows cast on the surface while the surface's Constant
shading is maintained.
 
REFERENCES
==========
 
If you have any questions concerning the information contained in this
article, contact support@softimage.com by e-mail.
 
Additional query words: si si3d si3dmat
======================================================================
Keywords          : si si3d si3dmat
Version           : IRIX:3.7,3.71; WINNT:3.7,3.71
Platform          : IRIX winnt
Issue type        : kbhowto
=============================================================================
Copyright Microsoft Corporation 1998.