HOWTO: Use the Up Vector Constraint with the Camera
  
PSS ID Number: Q173293
Article last modified on 09-02-1997
 
IRIX:3.51,3.7; WINDOWS NT:3.51,3.7
 
IRIX NT WINDOWS
 

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The information in this article applies to:
 
 - Softimage 3D for IRIX, versions 3.51, 3.7
 - Softimage 3D for Windows NT, versions 3.51, 3.7
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SUMMARY
=======
 
This article provides an effective method for controlling the camera's up
vector so that flipping does not occur. The procedure makes the up vector
follow the "point of view" of an animated object:
 
1. Select an object.
 
2. Create three nulls:
 
   - Place one null in front of the object.
   - Place one null in the center of the object as its "point of view".
   - Place one null on the y-axis directly above the "point of view" null.
 
3. Make these nulls children of the object so that they follow the object's
   movements.
 
4. Select the camera and constrain its position (Constrain -> Position)
   to the null in the center of the object.
 
5. Select the camera's interest and constrain its position to the null
   in front of the object.
 
6. Select the camera, choose Constrain -> Up Vector, and pick the null
   directly above the object's center on the y-axis.
 
7. Animate the object as desired.
 
Now when the object moves, the camera's up vector is correctly oriented
because it is constrained to the null above the object.
 
REFERENCES
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If you have any questions concerning the information contained in this
article, contact support@softimage.com by e-mail.
 
Additional query words: si si3d si3dcam si3dconst
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Keywords          : kbgraphic kbtshoot
Version           : IRIX:3.51,3.7; WINDOWS NT:3.51,3.7
Platform          : IRIX NT WINDOWS
Issue type        : kbhowto
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Copyright Microsoft Corporation 1997.