After updating to Unity 5.6 my additive animations are not working. It has some really strange behavior. The Editor says it is playing, but it isn’t and if I fiddle with the controls in the editor it starts working again. Here is a video of the behavior that I am talking about. Notice in the beginning that the look animations are not playing but as soon as I touch the layer weight the animations switch on and start working normally.
My project is really large so the upload fails, and when I attempt to isolate this in a smaller project I can’t reproduce the problem.
I think I may have found the problem, at least a work around. At some point I switch to an override controller, and the animations stop playing. Starting them up again manually after switching the controller fixes this, but this wasn’t something I had to do before 5.6. Basically when the override controller is set the animations are stopping.
I believe I understand the circumstances leading up to this.
There is a pose here that is additive with a reference frame. At some point in the past I needed to turn off the loop flag for this because of another bug (which appears to be fixed now) it relied on the behavior that Mechanim would maintain the last frame of the animation. When the override controller is switched it used to keep that animation on the same frame and just switch them. In 5.6 it seems to get into a state where no animation at all is playing on the additive layer. I believe touching the editor window triggers Mechanim somehow restart the default animations, which is what needs to happen.
So when the controller is switched out I can replay the animation or I can set the looping flag on them. This behavior is different in 5.6, but I am not sure you would consider this a bug.
Can you try to just reimport the file that containt your additive animation? there is a know issue with imported animation clip in 5.6 if you change them after the original import.
This might me related to another bug I just discovered in the context of Animator Layers: In 5.5.2, my layers behave as they should: working independently from another. Since 5.6.0, this behaviour is broken. The statemachine still appears to work (=displaying correct states and transitions), but the controlled scene objects no longer react to it, or behave incorrectly.
I submitted this as bug #909361, including a testcase.
