Need help rigging the hip joint

I’ve been experimenting with all-bone driven rigs, using fan bones to keep hinge type joints from flattening out, which works well. I’m trying to extend the idea to a joint that moves in two dimensions, namely, the hip joint. It’s very frustrating. I’ve tried several things, but there is a misshapen trench between the leg and the pelvis in the front that I can’t seem to get rid of.



So, I thought I’d put the blend file on line to see if anyone could take a look at it and maybe suggest how to fix that joint.

I tried your fan bone setup on a cylinder and it smooths nicely the outer side of a joint but still has those inward vertices on the inner side. Your fan bone setup works very nicely for the butt, but the front side has the usual problem.

You could add a bone parented to the hip whose head is somewhere above the origin of the thigh bone, add a “stretch to” constraint to it, pointing to the calf bone and then slightly weight paint the area inside the thigh to hip joint using this stretching bone.

Doesn’t sound so elegant as your fan bones, but some solution like that could work.