HOWTO: Build an Animated Revolution
  
PSS ID Number: Q173633
Article last modified on 09-10-1997
 
IRIX:3.7; WINNT:3.7
 
IRIX winnt
 

======================================================================
---------------------------------------------------------------------
The information in this article applies to:
 
 - Softimage 3D for IRIX, version 3.7
 - Softimage 3D for Windows NT, version 3.7
---------------------------------------------------------------------
 
SUMMARY
=======
 
The purpose of this article is to show you how to build an animated
revolution. For this example, you should use NURBS curves. However, you can
also use PATCH curves but the seam will be more visible when you close the
curve.
 
MORE INFORMATION
================
 
Step-by-Step Example
--------------------
 
1. With Modeling Relation turned on, create a profile curve in the Front
   view.
 
2. Duplicate the profile curve. You will need one copy more than the number
   of subdivisions (for this example, you need eight subdivisions), so you
   need nine curves.
 
3. Skin them in order beginning with curve1 and ending with curve9.
 
4. Pick curve8, and write the following expression:
 
   Affected Element: Spline8.roty
   Expression: Spline9.roty * 7/8
 
5. Pick curve7, and write the following expression:
 
   Affected Element: Spline7.roty
   Expression: Spline9.roty * 6/8
 
6. Do the same expression for curve2 to curve6, but modify the multiplier:
 
   Curve6 - 5/8
   Curve5 - 4/8
   Curve4 - 3/8
   Curve3 - 2/8
   Curve2 - 1/8
 
   Note that it is not necessary to write an expression for curve1 because
   you are not rotating it.
 
7. Animate the Y rotation of curve9 along time, and look at the revolution
   that is building itself up.
 
REFERENCES
==========
 
If you have any questions concerning the information contained in this
article, contact support@softimage.com by e-mail.
======================================================================
Keywords          : si si3d si3dmo kbhowto
Version           : IRIX:3.7; WINNT:3.7
Platform          : IRIX winnt
Issue type        : kbhowto
=============================================================================
Copyright Microsoft Corporation 1997.