Hello, i’m trying to make a pose for a character who is sitting on the ground. I am using the Human rig from Rigify. However, however i make the rig, when trying to position the legs in front of the torso it creates this weird mass in the center. Any way to prevent this?
(Checking “Preserve Volume” does not get rid of the mass)
Is this autoweights? If autoweights, reweight whenever you change bone positions. (If manual weights, well, they still need to be made on the basis of fixed bone positions, but probably it’s easier to change the bone positions to meet existing weights rather than vice versa.) The base of the spine-- the pelvis bone-- is too low; it should be inside the mesh. But the origins of the thighs are probably too high for what you’re doing.
You’ll get some value out of posing the pelvis more rotated relative to the abdomen. When people raise their knees to their chest, as is happening here, their back rotates to accommodate that. They don’t just have the same back arch as when they’re standing up straight.
If this is a pose which you will be using and showing often, probably best to do some manual weight painting (if you haven’t already). Another choice is to use corrective shapekeys. You can add a shapekey, called “sit groin fix”, for example, go into edit/sculpt mode and manually fix it. You can then use that shapekey whenever the character sits down or add a driver to the shapekey which will activate it when the characters’ leg comes up to that angle.