Shoulder rigging

mrmagee1000

I was wondering if anyone had a good reference or tutorial for rigging shoulders. The image below pretty much explains my problem.

I've found quite a few good shoulder rig videos on YouTube, but they are all just animations and don't actually show the artist's process. I'm just not sure if I'm doing the wrong thing in terms of my poly flow, or how I'm rigging (maybe I need more bones?) or if the skinning is off.

Any advice would be great. Thanks!

monster

You can add a twist bone or two and that will help with the collapsing of the shoulder when you twist the arm. You can take advantage of your character having the sleeve on the upper arm to separate the skinning for the twist bone and upper arm bone. You are using Biped so you can enter Figure mode and enable upper arm twist bones in there.

Unless your character is going to have his arms raised most of the time, I wouldn't worry about the arm pit.

Mrfred

+1 to monster respond...

try using the prebuild shoulder twist bone, if that solve your issue( it should) try using custom shoulder twist bone instead. The biped twist bone are kinda stupid and some game engine don't like them + you can't really control them.

Using a lookat + 2 dummy/point gives the animator more control and allow him to be quite precise about the shape he desires.

mrmagee1000

Thanks guys! Yeah, I had a biped shoulder twist in there and it was worse for some reason... (I was probably skinning it wrong or something) The shoulder would twist even worse than this and all of the verts would twist down almost into a point. But after hearing what you said, I will go back and play around with the twist links some more. I might try what Mrfred said too because I know Unity in particular doesn't like biped twist links... It's kinda goofy.

I like what Monster said about having the sleeve. It "is" very convenient for breaking up the skinning. However, my next character is an MMA fighter who won't be wearing a shirt. That's partially why I wanted to get this shoulder problem resolved so that I don't have to fumble around a lot while rigging next time. But what you guys are saying sounds good! I'll definitely play around with it and see what happens.

Thanks!

poopipe

engines not liking biped twist bones is simple to solve by skinning to a deformation rig that's constrained to the biped.

you should do that sort of thing as a matter of course because it allows flexibility in bone orientation and hierarchy on your export rig.


.. for your naked dude- id be adding helper bones to deal with large muscle deformations on specific areas like the armpit/traps/pecs. you tend to spend a long time chasing weights and getting nowhere if there isn't rig support.

mrmagee1000

When you say "skin to a deformation rig that's constrained to the biped", does that basically mean rigging bones and/or dummy objects in place of the default twist links and linking them to the biped in the same spots? Or are you talking about something more complex?

acitone

Sucks that poopipe didn't come back to respond, he seems to have some good rigging methods.