PDA

View Full Version : Ugly creases on hand joints



soletread
06-Jun-03, 13:27
Just when I thought I had this program waxed.

Take a hand mesh. Modeled in a 1/4 closed position. This is under advice from many sources. (the 1/4 closed position that is).

Now add bones and create vertex groups etc.

All done nicely. I think.

Close the fingers, beautiful. Nice creases etc.

Now extend the fingers straight as in a fully opened hand.

Not nice....the verteses around the joints deform inwards (only at the top) and the bones are straigt out, not bending up or anything. So now you have a very lumpy top of finger.

I have tried changing weights etc. No go. I have overlapping vertex groups assigned around the joint areas. That doesnt help either, although it does lessen the abruptness of the crease if you know what I mean.

Is this really a modelling problem, should I actually model the hand straight out? Is there a way to fix this without having to remodel all over again..... :(

Someone please say yes. ;)

Cheers

Desoto
10-Jun-03, 21:18
Yes. But I don't know how..I just wanted to sound encouraging. Actually, I'm really posting to request that you post a screenshot of the problem.

soletread
11-Jun-03, 05:03
I wish I could post a screenshot, I will try find a server somewhere.

I think what I have figured out is that its not actually the mesh that doesnt deform correctly. That is, bending back from a curved position as in the case of a finger for instance.

But it is actually that the verteses are actually "set" at their angle when applied to a particular vertex group which is then assigned to a particular bone.

What is actually happening is that the Mesh faces are behaving correctly in that their angle is proportional to the bone. Hmm, not making much sense here.

I have tried different weights and overlapping the vertex groups with some improvement.

I just cant figure how I got one hand to work (by accident) and the other I am battling with. (Same mesh and same bone structure)

Thanks for the encouragement.

Cheers.

---

theeth
11-Jun-03, 11:36
I just cant figure how I got one hand to work (by accident) and the other I am battling with. (Same mesh and same bone structure)
Then, you could copy the working hand, flip it and paste it back on the one that doesn't work.

All you have to do is this:
shift-d, copy the hand that works (in edit mode, of course)
p separate it from the rest of the mesh
select the hand alone and rename the vertex group to match on the on the other side (replace .r by .l or vice versa)
rejoin (shift-j) with the rest. It will have the correct vertex group name and should deform correctly like the other.

Martin

soletread
11-Jun-03, 15:21
Sure thanks for the tip. [!]

It appears that the flipping does not carry this info accross like pose flipping does. (Doesnt rename the vertex groups.) Its not too difficult to rename them though. :-?

But it looks like the one hand works better than the other due to the placement of the bones within the mesh. In other words, how far they are from a particular face, how deep in the middle etc.

I tried to flip the Right hand bones to a left hand version, but then all the constraints are lost. :| I guess it pays to do the flipping before.

Solution: 1) model hand 2) Create hand bones 3) Creat vertex groups 4) Assign vertex groups to hand mesh 5) Flip hand bones and hand mesh 6)Rename hand bones and hand mesh vertex groups in the flipped hand 6)create IKs and contraints in both hands 7) Rename hand bones and hand mesh vertex groups.

Oh well. I think I am going to remodel the hand in a flat position and hope it bends inwards without a problem. :D

Thanks tho, to all.

Cheers

----