So i’m back to doing this again and everything was running quite smoothly, which means something confusing will happen soon.
The arms (and other blend shapes) are really tricky. Due to them being completely flat they can only move in certain motions without becoming invisible. Distorting and twisting the drawings to use them as blend shapes is an interesting technique though, it allows the looped texture of an object to be animated with and controlled in 3d software. It also gives you the option to mix up 2d and 3d animation quite nicely.
I am finding the right arm to be especially difficult as it will need to move more than the rest and has the most complicated paths. Linking body parts together in the hierarchy is proving to be annoying too because moving a limb via blend shapes does not change it’s position in the world space, just it’s appearance – so a hand or foot won’t follow the bent arm or leg.