Back Story. I have some anim loops using root motion, but they don’t have the same start and end frames – the body in a slightly different position, so there is a visual glitch – there doesn’t seem a way to blend the animation back into itself when looping.
This brief guide is going to use a Level Sequencer in an empty level to fix the anim loop.
First add your Character to the scene, then add a Level Sequencer
-Click the + Track button, then choose Actor to Sequencer and choose your Character.
Then in the Character track click the + after the characters name and choose your Animation, like in the image below:
Once the animation is added, duplicate it.
Select the purple track, copy, then select the animation track move the play head to past the end of the purple track and paste, this extends the character track to fit. You may need to move the red sequence end marker along.
R-Click the copied animation then choose Match With This Bone in Previous Clip / Root – this will move the second animation so that the roots match -the copied animation continues from the end position of the first.
Sliding the second animation to overlap the first creates a matched blend between the two animations, you can control the length of the blend.
Adjust the Red and Green Start and End Playback Range markers. This is the part that gets exported.
For a good loop put the mouse over the Blend making a note of blend duration (e.g. it will say something like Ease in: Sinusoidal Out (16 frames)). Trim that amount (16 frames in this case) from the front of the first clip, by moving the red Start Marker in that many frames.
Put the end marker on the end of the blend. You may have to zoom in to see this.
With that set up, Rclick the Character Name and choose Bake Animation Sequence. That it
Theres also this video which also explains the FK animation tools neatly