Anim8or Community

Please login or register.

Login with username, password and session length
Advanced search  

News:

An update to Anim8or, v1.00b, is available with a few bug fixes. Get your copy HERE. See the "ReadMe" file for details.

Author Topic: Better shoulder deformation?  (Read 1312 times)

JunkerKun

  • Newbie
  • *
  • Posts: 26
    • View Profile
Better shoulder deformation?
« on: September 10, 2014, 06:19:43 pm »

Hey there. I have a problem that is, I think, called "candy wrap effect". When I rotate a shoulder bone the skin gets wrapped around it. I haven't found a good solution yet. Maybe someone here has ideas?

The second screenshot shows the problem and the first one shows my rig (oh God, it's a baaaaad rig).
Logged

Water Music

  • Jr. Member
  • **
  • Posts: 86
    • View Profile
Re: Better shoulder deformation?
« Reply #1 on: September 12, 2014, 12:54:32 am »

Getting nice-looking joints that work at all angles is the hard part of this game.  To start, I'd recommend minimizing the number of vertices right at the joint.  For the parts of your model that stay fairly static you can load up as much detail as your system can handle, but at the joints the fewer points you can get away with the easier your life becomes.

Another common issue with the shoulder (even amongst professionals) is to place too much emphasis on the upper arm bone, and not enough on the clavicle.  You will notice that if you keep your collar bone down you can't raise your upper arm  much more than parallel with the ground.  The same is true with your modelling: if you spread extremely high motions of the upper arm over both bones you will significantly lessen, but not entirely remove, the difficulty of getting uniform volume in the joint.

The last thing is to bias the shoulder opening on the body and the upper arm to favour a forward motion with the arm, since the arm rarely goes very far backwards.  I hope that makes sense, as it's a bit hard to describe.  Basically if your body was a rectangle and your arm was a rectangle coming out of the side, then where they meet the back vertices go out to the side more than the front vertices do, and you will keep more volume in the shoulder as the arm swings forward.

As I said, it's tricky but hopefully this will at least get you started.  And I, by no means, consider myself an expert on the subject.  There should be some tutorials out there on the web, somewhere, as this is a very common problem.
Logged

nemyax

  • Full Member
  • ***
  • Posts: 214
    • View Profile
Re: Better shoulder deformation?
« Reply #2 on: September 12, 2014, 10:17:46 am »

JunkerKun
You can use a setup where the upper arm has two bones at the shoulder, and one bone is the child of the other. You animate the parent bone, and configure the child to automatically compensate for the parent's rotation. The child bone affects the vertices nearer the shoulder, and the parent bone the vertices nearer the elbow.
That said, I'm not sure Anim8or would let you rig it like that.
And note what Water Music says about the collar bone. The pose in your screenshot is impossible. You can't lift your arms like that and not have your shoulders come up above the height of your chin.
Logged

JunkerKun

  • Newbie
  • *
  • Posts: 26
    • View Profile
Re: Better shoulder deformation?
« Reply #3 on: September 12, 2014, 02:52:35 pm »

Quote
And note what Water Music says about the collar bone. The pose in your screenshot is impossible. You can't lift your arms like that and not have your shoulders come up above the height of your chin.
Yeah, I forgot to lift clavice bones. GOnna do it right now =)

Quote
To start, I'd recommend minimizing the number of vertices right at the joint.  For the parts of your model that stay fairly static you can load up as much detail as your system can handle, but at the joints the fewer points you can get away with the easier your life becomes.
I try to make the whole vertex count as low as possible - I want to use models in a game later. Aaaaand I don't really think I can cut points near joints lower than now - they would look even more horrible than now.

Quote
There should be some tutorials out there on the web, somewhere, as this is a very common problem
But no tips in general. Almost every tutorial was for 3D Max and they used something that is available only there.

I think the easier way would be to cut arms completely and make them "Tomb Raider 1 style". I wonder what should I hide the joints with though. Shoulder pads?
Anyway, thanks for the help. Will try to make something about those joints...
Logged

johnar

  • Sr. Member
  • ****
  • Posts: 812
  • Make it, Move it--Give it Life
    • View Profile
    • youtube vids
Re: Better shoulder deformation?
« Reply #4 on: September 14, 2014, 12:12:40 am »

Quote
I think the easier way would be to cut arms completely and make them "Tomb Raider 1 style". I wonder what should I hide the joints with though. Shoulder pads?

 Thats defineately another option. I did that with a froyd type character. He has a t shirt and i poked his 'seperate' arrms into the holes of his t shirt. Shouldeer pads should work well. One thing i did need to do was add some 'fix' morph targets to the sleeves, as in some poses/movements, his arm would poke through the shirt. Made morphs like 'Rsleeve fwd', Rsleeve up'  etc...
 You could do the same with morphing shoulder pads.... allows tweaks for troubles
Logged
%