Nonlinear animation allows you to work your animation at different levels of control. At any time you can go back and modify data at the lower levels, without the need to begin again and redo all your work. It gives you high-level control over animation because you can layer and mix sequences in a nonlinear and non-destructive way. It helps you reuse and fine-tune animation you’ve created with keyframes, expressions, and constraints.
Nonlinear animation requires the animation mixer. In it, you create animation or shape sequences, transitions, and mixes. It takes all the underlying animation data and packages it into clips. Each clip is an instance of an animation or shape source that you create. On the frames “covered” by the clip, the data stored in the source drives the animation.
Once you have a library of animation, shape, and audio sources created, you can bring them into the mixer in a completely non-destructive manner (the original animation data stays untouched), making it easy to experiment with the animation. After you have started mixing, you can always go back and change the original data, and all your changes will automatically be applied; or you can add animation on top of the original animation source, as you may want to do when cleaning up or adding offsets to motion capture data.
The animation mixer is well-suited for editing existing material and bringing together all the pieces of an animation. In it, you can assemble all the bits and pieces you’ve imported from different scenes and models and help you build them into a final animation.
If you’re modifying someone else’s animation, you don’t really have to deconstruct their work—just add a layer with your own animation. You can even modify the existing animation in a clip with a clip effect, acting as a separate and removable layer on top of the original animation, or mix a clip with fcurves on the object over the same frames.
Anything that can be used in the mixer has two parts: sources and clips.
• First you store animation (fcurves, expressions, constraints, etc.) or shape deformation as a source. You cannot create an audio source in Softimage, but you can use a number of different audio files as sources.
• Then you instantiate that source as a clip on a track in the animation mixer. You can create any number of clips (instances) from each source.
Sources
Sources are just that: sources of animation, shape, or audio information that you’ve stored.
Every time you create an animation or audio source, it is saved at the scene level under the Sources > model folder.
In addition, a copy of the source is listed (displayed in italics) in the model’s Mixer > Sources > Animation or Audio folder for convenience.
Shape sources are not stored at the scene level because the shapes need to be kept with the object’s clusters to which they’re referring. They are stored only in the model’s Mixer > Sources > Shape folder.
• For more information on action sources, see About Action Sources and Clips.
• For more information on shape sources, see Shape Sources (Keys) and Clips.
• For more information on audio sources, see Audio and Animation.
Clips
After you create a source, you can drag it onto a track in the animation mixer where it becomes a clip. A clip is just an instance of the source meaning that you can create as many clips as you like from a source.
When you modify a clip, you don’t change its source, but when you modify the source, you change all clips that are instanced from it (with the exception of clips that come from expression and constraint sources).
Compound Clips
A collection of clips can be packaged into a compound which allows for operations to be done at the level of the entire compound. Compounds are a way of packaging different clips together so that you can work more easily.
For example, you could package one compound karate “move” that’s made of a kick, punch, and turn, and then cycle, copy, scale, or reuse this compound clip on another character.
One of the most powerful features of nonlinear animation is that fact that you can mix the weights of two or more clips (action or shape, but not audio). When two or more clips overlap in time and drive the same elements, you can mix them by setting weights that control their relative influence. The higher the mix weight, the more strongly a clip contributes to the combined animation.
You can have a weighted average of a mix (the default) where the results are mixes that fall between the values of the separate clips, or you can add the values of the clip on top of each other, as is often useful when animating different shape clusters together.
You can also mix the weight of an action clip with fcurve animation on the object at the same frames—see Mixing Fcurves with Action Clips.
For more information on mixing in general, see Mixing and Weighting Clips.
If you’re mixing shape animation clips, see Mixing the Shapes’ Weights for additional information specific to shapes.
Autodesk Softimage v.7.5