I’m about to try and rig a specific animation and I was looking for advice on how to go about it.
I have a character who I want to transform from a human to a monster. I’ve modelled the mesh transformation with shape keys - shaped one normal human, and shape two is the transformed monster. I have a working armature rig for my character (a mixamo rig) but the monster shape is much bigger than the human armature.
I’ve created a new, larger armature for the monster form and have added a new armature modifier for it, which works nicely as the WP vertex groups are the same for both armatures.
But is there a way for me to transition between the two armatures as part of the animation? I don’t see an ‘influence’ slider or anything obvious.
Hi, I would advise approaching the scale change as part of the armature itself, using a single scale property on the root bone. I can’t see an easy way of transferring control from one armature to the other in a continuous, hiccup-free way. I never tried something like this so I could well be wrong, but I’d do it differently, scale the rig and do the shapekey-based deformations in this new space.
I was wondering if this was possibly the case. The main issue I have about this approach is that its not so much a uniform scaling for the monster character, but a change in proportions - wider shoulders, longer arms, shorter legs etc. Would this approach still work for this or should I rethink the design of the monster?
So, the thing is it depends quite a bit on how you rigged the character. I see two possible ways ahead :
you could join both rigs (make sure the bones use different names and armature layers before you do that), and then make your deformation bone layer copy the monster’s bone transforms (this can be animated with the constraint influence). But this assumes that you’ve split your rig into layers and the deformation bones are separate from the rest, only copying transforms from controller or IK bones and never animated by themselves.
you could keep your human rig as a base and insert “offset bones” into it whose sole purpose are to adjust the rig’s proportions to that of the monster, mostly through scaling or repositioning.
Regardless of the technique, the transformation should be driven by a single property (say on the root controller).
Are you going to need the transformation to happen several times over ? if yes I would invest some time into getting a nice setup that doesn’t become a nuisance if you ever need the transformation to happen while in a different pose, or in a different context.
You don’t have to scale the armature, or a root bone; you can scale individual bones. Scaling bones preserves the placement of bones (relative to the mesh) and their children and their children’s children, while shapekeys do not.
So you manage proportions with bone scaling-- which can be non-uniform, but then you should consider looking at scaling inheritance options-- and only afterwards, you manage anything that bone scaling can’t do, with shapekeys.