I’ve personally been abusing shape keys for mesh deformation on human characters (knee bending, neck movement, etc) because I find impossible to have good and realistic deformation using only or mostly the armature and it’s weight paint. Not sure if I simply suck or Blender doesn’t have a reliable and stable weight painting system, because even using blurs and smears to have a good gradient, the deformation always sucks and weights keep “leaking” into neighbor bones undesirably. Ultimately, I end up with dozens of shape keys (shape keys for specific angles for knee bending, for every single part of the fingers, etc).
The problem begins when I try to recycle everything into a new character. When the new character has a considerable difference in height and facial structure, when I adapt the armature for the new proportions (scale the bones, save as shape key, apply new scaled pose as rest pose then blend the basis shape key with the new scale shape key), most of the existing shape keys for bone movement don’t translate well so I have to redo many of them with takes a lot of time and tedious work.
So, in the end, I ask: Is it worth to invest in upgrading the armature with more complexity, such as more bones, drivers for the bones, more bone constraints, etc? Are existing armatures and bone weights more recyclable for new different characters than shape keys? I fear wasting time creating complex armatures that only work for that specific project. How do you guys reuse these stuff for new projects?
Thanks in advance.
TL;DR: What is the easiest and most effective way to create a new character from an existing one while having to re-do the least amount of things possible regarding armature and motion shape keys?
It sounds like you weren’t happy with your deformations, so you pursued corrective shapekeys as a workaround for that; now that you find that making corrective shapekeys is too cumbersome, you’re pursuing reuse as a workaround for that.
But the easiest and most effective thing to do here is to learn how to get good deformations quickly and stop pursuing cumbersome workarounds. You shouldn’t be looking at reuse unless you’re thinking of a low quality crowd scene or something. There’s a reason that there’s a workflow: you make the mesh, then you make the rig to fit that mesh. The reason for that workflow is because it gives good quality and, in the hands of somebody that knows what they’re doing, is time efficient. More time efficient that being handed a rig and a mesh and being told, “Make this particular rig work well with this particular mesh.”
You can learn to weight a model quickly and well (although your weights may not be the issue-- often, people blame their weights for issues that arise from the rig or from the mesh.) There’s not some single, silver bullet to learn how, it’s just a collection of techniques. You could consider for asking for help on that: “Here’s a mesh, here’s the animation I need for it, here are the problems I’m having with my first draft attempt at rigging it-- any advice?”
If you ever hire somebody to rig something for you, and you’re happy with it, ask them if you could hire them to explain how they rigged it with you over Discord or something. At the same rate you were paying for rigging. I think most would be happy to do so. But you don’t have to hire somebody either, you should be able to get advice for free from us BA suckers.
Now, if the mob told me I needed to change a model and I couldn’t change the rig or weights, or else they’d kill my family, what I’d do is pose it to as close as I could get it to how I wanted it, and then edit in the changes I couldn’t get onto the pose. Only the changes I couldn’t get onto the pose. That would keep the weights (and the joints) in the right place.