View Key Interpolation
Interpolation is a process used by the computer to determine how to treat the frames that exist between each keyframe created by the animator. Essentially, the computer is “guessing” or “projecting” how those in-between frames, as they are called, will behave. In some cases, an animator may use but a few keyframes for a particular element, and let the computer do the work. In other cases, an animator will create many keyframes in a shot, with few interpolated frames in between. This is particularly true of character animation.
Motion Keyframes (position, rotation, scale) offer the following interpolation types (as of release 13):
- Spline
A smooth transition from keyframe to keyframe will be the result. Some refer to this as a “computery look”, if left without finessing. - Linear
A straight transition from keyframe to keyframe, with abrubt changes as defined by the keyframes themselves. Effective for maintaining velocities while rotating. - Step
This method “jumps” to the keyframe value at a given time. In the graph editor, a literal “step” shape is drawn between each keyframe. Animators use this type of interpolation when performing pose to pose animation, as this method allows the animator to see only the keyframes, but in the proper time as they appear within the timeline. Final animation rarely uses Step, as it is just a tool to aid in character posing.