Sweep

The Path->Sweep command in the Motion module allows you to create complex models by sweeping one curve along another curve. Unlike the standard extrusion on a curve, Sweep allows you to animate the cross-sectional curve so that the resulting model reflects that animation. For example, a simple keyframed rotation applied to the cross-section curve automatically creates a surface with a twist in it. Such an effect was previously tedious to do.

In cases where the sweep path is closed and three-dimensional, Sweep adjusts the "twist" in the cross-section so that the beginning and end join smoothly.

Procedure

1. Create two curves: one curve to define the cross-section, and one curve to define the path. The cross-section or path curve can be animated.
   
   Note:
   
   NURBS curves may be used for either the cross-section or the sweep path. The curve, however, is computed by converting any linear NURBS curve into a linear curve and any quadratic or cubic NURBS curve into a Cardinal curve.
   
   
2. Choose the Path->Sweep command.
   
   The Sweep dialogue box is displayed.
   
   
3. Set the parameters as desired.
4. Pick the cross-section curve, then pick the path.
   
   The effect icon and the initial version of the model appear.
   
   Note:
   
   This version of the model does not incorporate the animation applied to the cross-section.
   
   
5. Play back the scene to initialize the animation and create the final version of the model. Make sure that you start the playback at or before the Start Frame set in the dialogue box.
6. Choose the Effects->Freeze Effect command in the Motion module to remove the animation and freeze the model with its current geometry.

Note:

You can further modify the animation on the cross-section or path before freezing the effect. Remember to play back the effect to update the animation and final version of the model.

Parameters

Start and End Frame

Sets the start and end frames for the animation of the cross-section.

Capping

The model is capped when the sweep path is open and the cross-section is closed. As the playback progresses, the model slowly changes to reflect the animation on the cross-section.

Frame Rate

For the motion timing to be correct, this option must be set to the same frame rate being used in SOFTIMAGE 3D, usually 30.0 or 24.0 frames per second.

Last updated 02-apr-1998