When two animation, character, or camera animation clips on the same track do not overlap, the animation is blended by interpolation. When two clips overlap, the blend is called a cross-blend.
You can cross-blend animation, character, camera animation, and constraint clips. Cross-blending animation clips can create smoother animation. For example, blending constraints clips is useful when you want to create the impression that a model is under the influence of many actions.
Constraints cross-blend A. First clip’s Fade Out handle B. Selected clip’s Fade In handle C. Blend area D. Selected clip
When an Animation, Character, or Camera Animation track’s Animate option is active, the beginning and end of cross-blends on these tracks are represented in the FCurves window by small vertical lines.
To create a cross-blend for camera shots, see Creating a cross-fade effect with camera shots.