Looping Animation Has a Hitch
A stutter at the point where a cycle repeats
Also known as: Animation loop stutter · Loop hitch · Walk cycle loop skip · Idle loop pop · Duplicate frame loop · Looping animation not smooth
Quick answer
A looping animation hitches when its first and last frames show the same pose, so the pose is held for two frames at the loop point. Remove the duplicate last frame, for example by setting the end of the range one frame earlier, so the last frame leads naturally into the first. Also check that the curves have matching tangents at both ends and that the root does not jump or drift between the end and the start.
How to fix it
Play the loop several times in a row in your tool to see the hitch, and step through the last frames. For cycles with movement, make sure the position of the root continues smoothly, or use root motion and let the engine handle it. In idle animations, give the pose subtle variation across the loop so it does not look robotic. Check the loop setting on the animation in the engine.
Tools that use Looping Animation Has a Hitch
See also
Walk and Run Cycles
The looping base of character locomotion
Keyframes and Interpolation
Poses in time and how the computer fills in between
The 12 Principles of Animation
Foundations of believable motion
Root Motion
Movement driven by the animation, not the controller
Animation State Machine
Graph of animation states and transitions
Animation Frame Rates (24, 30, 60 fps)
Which frame rate to animate and export at