PRB: 3D Texture Anomalies (swimming) with hrcExplode Effect
  
PSS ID Number: Q175821
Article last modified on 11-07-1997
 
IRIX:3.7; WINNT:3.7
 
IRIX winnt
 

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The information in this article applies to:
 
 - Softimage 3D for IRIX, version 3.7
 - Softimage 3D for Windows NT, version 3.7
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SYMPTOMS
========
 
When a 3D texture is applied to a model that has an hrcExplode effect, the
3D texture does not remained fixed in one place (swimming effect) on the
model's surface, even though the 3D texture is not animated.
 
CAUSE
=====
 
The 3D texture's projection is based on the hrcExplode parent's center, so
when the children of the hierarchy move in different directions, each child
receives a different 3D texture pattern as it changes position.
 
This is similar to a slide projector projecting an image on a moving
object. As the object moves through the projection, its surface receives
the pattern that is available at that moment (in SI terms at each frame).
 
RESOLUTION
==========
 
Complete the following steps to create a 2D texture map based on the 3D
texture:
 
1. Apply the 3D texture to a grid.
 
2. Pan the camera close enough to the grid so that no black background is
   visible.
 
3. Render an image with a square resolution (such as 512 X 512 and a pixel
   ratio of 1.0).
 
4. Apply the 2D texture map to the Parent in UV mapping projection of the
   hrcExplode hierarchy.
 
The children models will receive the texture.
 
The result is not exactly the same as the 3D texture, but the "swimming"
effect no longer occurs.
 
STATUS
======
 
This behavior is by design.
 
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
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Keywords          : si si3d si3
Version           : IRIX:3.7; WINNT:3.7
Platform          : IRIX winnt
Issue type        : kbprb
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Copyright Microsoft Corporation 1997.