Non-roll shoulder setup


#1

Hi all,

Last week I was using a new arm setup for a cartoon character with no roll for the shoulder area, just with the propagated twist from the wrist joint. Although it would not do the trick for not-symmetrical section arms (in wich you can recognise the orientation of the elbow) I have found it very very useful for cartoony characters with tube-shape arms, cause there’s no need to add resolution in the arm mesh for a correct twisting and there’s no flipping issues.

I’m not quite sure if you guys have already used this kind of rig, or maybe you find it kind of crazy and weird setup. So please if you could take a look and let me know your thoughts.

http://www.luvictu.com/reel/nonrollshoulder.mov

Thanks!


#2

Looks interesting!
Must be early in the morning but I don’t quite understand how you could take out the twist in an IK setup, did you do a custom one, or do you have a counter twist bones?


#3

that looks brilliant!! (the char looks a bit like donald duck without his beak) can you share how you did it? it would be the perfect solution for one of my character!


#4

One way to do it is to have counter rotation nulls along the arm to which you weight to, and those null have their own upvector.


#5

Hi guys, and sorry for the late response.

I’m not actually using counter-rotation, but a traditional roll-bone system with not twisting at all. The point would be to use the standard 2x2 roll bones, each one drived for an IKHandle attached to the main IK chain with pos constraints, so they would never follow the twist of the real shoulder / wrist bones. These IKhandles are pole-constrained to locators for its own twist control. The geometry is binded to the roll bones.

On the other hand, I’m using a wire-deformed plane (or whatever poly object), with the wire curve attached at the start and end of the shoulder bone (all the same for the elbow bone) to drive, via a rivet constraint, the pole vector (and so, the twist of the roll bone) with TOTAL independency of the twisting of the main IK chain. This way, we can isolate the twisting of the roll bones without flipping issues, and therefore we can distribute the “total” twisting from one point to another in the way we prefer.

Cheers!


#6

Indeed, this all sounds very interesting and your demo has a lot of promise. Was just wondering if you could post a demo scene file. It would really help to dissect it and understand everything going into this.

Thanks.


#7

I second that, a small scene file would be very helpful to understanding what you’ve done here.

Cheers,
Pete


#8

Hi guys,

You can download this scene file (maya 7.0):

http://www.luvictu.com/reel/nonRollShoulderRig.mb

I have tried to simplify the scene in order to leave just the key things for the arm setup. Hope it’s still working :shrug:

The point would be to play with the upVector control and see how the mesh is not twisting at all while keeping the right elbow orientation if we bend the arm. Please let me know your thoughts.

Bye!


#9

Any chance of getting a 6.5 version, or a .ma? I’m sadly lacking in the newest versions department. I think I do somehting similar in some of my rigs, but I always like to compare notes, as it were.


#10

An .ma file would be great, I have 6.5 also.:slight_smile:

Pete


#11

Hey, I’ve uploaded a .ma version of the file. I’ve already changed it to version 6.5. It seems to work fine although it’s still showing error messages when loading. Anyway, let me know…

http://www.luvictu.com/reel/nonRollShoulderRig65.ma

Cheers!
V.


#12

Thanks for posting these. Very interesting setup.


#13

Dig your arm set up. Arm set up is the bane of my existance. I am assuming you can set it up FK as well? Can’t wait to get home and try it.


#14

hey victor,

Really nice non-roll shoulder setup you have there. Now the animators can twist the arms around without having to worry about the twist in the shoulders! Great stuff! :thumbsup:

Just one thing: I notice the entire arm up to the forearm region actually moved when the pole vector control is moved. Is that what you intended to do?


#15

[i]walbergstudios wrote: I am assuming you can set it up FK as well?

[/i]I have not set it FK actually. The fact is that I use to bend the elbow joint in any axis when working in FK in order to avoid the twisting of the shoulder, so… but I’ll give it a try and see what happens.

[i]xenoid wrote: Just one thing: I notice the entire arm up to the forearm region actually moved when the pole vector control is moved. Is that what you intended to do?

[/i]Yes, this happens because the arm twist is propagated from shoulder to wrist and the wrist orientation is locked in global space.

Cheers!


#16

now y didnt i think of that!! lol… very nice idea u got here mate!.. thanx for sharing


#17

Why did you remove the video?The scenes don’t work either …

Please reupload


#18

Hi victor,

Thanks for sharing but unfortunately I cant seem to download any of these files… can someone kind enough to mirror them?? thanks


#19

I see, I see - this is cool man. In max you can do the same with a WSM path deformer, driven by a ik handle twist value - you completely lsolate the twisting to control it how you want. You could do the same in both maya and max, with a pole-vector driven bone, (thats your independance) driving a a bone or two’s average twist.


#20

eek or luvictu,would some of you guys want to record in camtasia(video says it all) how to do both:

  1. counter-rotation

  2. traditional roll-bone system

I am baging you guys pleaseeeee,please …