Microsoft KB Archive/173633

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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 ==


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.


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.


If you have any questions concerning the information contained in this article, contact 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.