I tried to rig this hand and also opened a thread about this topic. My hand gets always messed up and doesn’t look real after rotating the bones. Auto weight doesn’t work for my object as well. I used the Bone envelopes and it work a little bit but changing the size of the bones or the size of the distance didn’t make look it real.
It’s my first time rigging an object in Blender and i am sure there is a way to turn my hand into a realitic looking fist. Maybe someone can help me.
When you do automatic weights, then the influence of the bone on the mesh is based upon the bone location.
Looking at it i can imagine a problem area here
There is quite a gap between central bone and fingers, so their weight effect gets wrong.
The base of the hand gets too little weight, and ist gradually going to the fingers over a to large area
Also the fingers dont use the same bone structure.
The smallest finger uses more bones.
enlarge the central bone, so its influence is better spread over the mesh, bone weight is based upon bone location.
you might do all fingers with 4 bones, and use an IK constraint on the tips length of 3
( os the finger base bone wont move, and you set it with a fixed ofset to the central bone.)
make them all so that rotating over x axis is bending them, mostly correct perhaps the thumb needs little changes.
use a bit more faces on locations where the bendings will happen sudivide edges on the length of the fingers
small errors can be adjusted with weight painting later.
but auto weight still fails
and rotating the bone envelopes or changing the size doesn’t change anything.
Probalby I’m still doing something wrong because in some tutroials i watched they’re using a same hand like mine and it works perfectly for them.
Here is the way I solve the problem. Try switching bone display to “Envelop”. In my case the bone Envelop was huge! They were overlapping most all of the geometry around it! So I fixed the envelop to right volume around the bones, and problem went away for normal parenting with automatic weigh. Try it.
I didn’t use volume or set the volume that big in the first place. There is Blender bug some where.