You can set keys on a character set that already has an animation clip to affect the character set relative to the existing clip animation. This lets you layer keyframe animation on top of your nonlinear (clip) animation. The technique of applying keyframe animation on top of existing clip animation is nondestructive.

Placing keys on top of clips is useful in the following situations:

• You want to add new motion to your character.
• You’re satisfied with an existing clip but want to make subtle changes without destroying your work.
• You’ve created animation clip instances for various characters (for example, a street gang walking down an alley), but want to apply a unique walking motion to each character.
• You’ve created dense key data for a character (for example, with motion capture), and you want to adjust the motion without altering the keys.

To add additional keys to a character on top of its clip animation

1. Select the character you want to key.
2. Set keys—without changing any attribute values—at the start and end of the clip region you want to modify.

   These bounding keys delimit the start and end of the region where you will add keys to your character.

3. Set keys within the delimited region.

   These keys create add to your character’s overall animation.

4. Play the animation to make sure that the keys you added have the desired effect.
5. When you are satisfied with the keys you added, create a clip for them. See Create clips.
6. Modify the clip’s Weight attribute and curve to fine tune its motion. See Edit clip weighting.

   Layering keys on top of clips may have undesirable results if you create them over top relative clips, including cycled clips. If you want to create keys over a relative or cycled clip, make the clip absolute by merging it. See Merge clips.

Example

Suppose you have a clip of a soldier marching and you like the general motion, but you want to raise the soldier’s foot higher during the march. First, set bounding keys at both frames where the foot is on the ground, without changing any attribute values. Then, where the foot is raised, move it a little higher and set a key at this position. Create a clip for the keys and try different Weight values to tune the animation.