I’m trying to set up an aim offset for use with my mesh, using a layered-blend-per-bone node to restrict the aiming to the upper half of the body, and I’m running into an issue that I hope someone more familiar with pose blending could shed some light on.
The rig in question is IK-driven, meaning the structure of the rig isn’t all parented to some (used) bone of the skeleton. Instead the setup involves the core of the character being broken into pieces:
-a root/core (not the master “Root” bone, a center-of-mass bone) which radiates outward down to the hips and up to the head (thru the chest and spine)
-Two legs (starting with the glutes and upper thighs and moving down to the toes)
-Two arms, starting at a shoulder socket and moving down through to the fingers.
The rig is designed this way so that the IK solvers can work during animation; if the character’s hands or feet are meant to remain exactly in place while the core moves or twists, then the portion of the skeleton which contains the legs must not be a child of the core in the bone hierarchy (or else that core movement would move the legs and break the IK)
The problem is that this makes applying a blend to just the upper half of the body something of a nightmare. I can apply the blend to the torso and arms, and they’ll do that blending, but the constraint systems that keep them together come apart. The torso blends, and the arms blend, but the arms and torso begin to detach from one another since each piece of the skeleton seems to be calculating its blend separately in the LBPB.
The only way to get the arms and core inside the same branch of the LBPB is to grab at the master level, though, and doing that grabs the legs too. Essentially, there is no single bone which cleanly indicates where the upper body and lower body are split on the rig, which is preventing me from blending properly at that point.
Is there some way to EXCLUDE bones in a blend, rather than INCLUDE bones? i.e. tell it “blend everything BUT the bone trees starting here”? Or am I looking at completely refactoring my skeleton and all associated anims…?