I'm working on a project that will require 2 human models to interact with each other - often times 1 human will be performing an animation and the other human will be performing a separate animation. Syncing the 2 animations so they're timed correctly and are in the correct spots is tedious. Is there any tool for playing 2 animations at the same time so you could see the approximate timing of both?

Or, is there a good way to use an overlay or background image to approximate this better?

Oh wow. So, when creating an animation for just one of the skeletons Spine is smart enough to know how to keep them separate? Or, I suppose as long as I only highlight the skeleton and bones I'm actually animating with then it shouldn't matter.