Unfortunately, it’s not possible to have smooth blending and synchronization at the same time.
The call to animGroup.syncAllAnimationsWith(animatable) has been added to synchronize animations, but you may have a jump in animation just after this call because the frame calculated by animGroup just before the call to syncAllAnimationsWith may be different from the frame calculated just after the call, because the new frame will be calculated on the basis of animatable’s frame range + current frame. In general, these two calculations won’t give the same result (unless you’re lucky and call syncAllAnimationsWith at the right time!).
I don’t think there’s anything we can do to solve this problem. To improve the existing result, I think some people/games use specific transition animations to switch from walking to running, or any other pair of animations.
cc @PatrickRyan to be sure I don’t miss anything.
Note: for my tests, I used a simplified PG that makes use of some new features added in the latest Playground update (notably the AnimationGroup.weight property):