I’ve designed my model, it looks good in the original T pose, but when I move the body, such as arms up, I get this…
What on earth am I suppose to do about that? This is going to be a VR avatar, so when I move, how do I keep it from looking atrocious? If I were to modify the mesh in these poses, it would destroy the base pose look.
I’ve done what I can in weight painting.
If recommend corrective shape keys tied to the rotation of the humorus, but I don’t know if it would transfer to the vr program.
I’ve tried doing shape key drivers for the shoulders, the rotation thing always confuses me because its rotating ALL axis even when I’m just selecting one, so I just choose the axis that ends up giving me 1.000 on the shape key. BUT, the problem is, the beginning and end of the movement are fine, but inbetween my shoulder explodes in a mess of expanded geometry. I also don’t know if VRChat will utilize it, if it doesn’t that saves me the hassle, but still I need to fix the issue with the geometry while moving.
Also the rest pose is a T pose. So arms down is fine, but arms up results in that. Am I going to have to sacrifice the anatomy of the muscular structure to hide the horrible stretching?
I use the sculping tool. So frame by fame i sculpt each part that is creased. Its not professional, but it gets the job done. 
Have you tried smoothing out the weights on the mesh?
and use blur brush in weigh paint mode to smooth it out
Every time I adjust it for one position, it destroys it in another.
Yes, no matter how I paint the weights, its an abomination in another pose. Whats more, if I move the arms up in IK movement, its different then if I were to rotate it. Rotated looks a thousand times worse and I just have no idea whats supposed to be what before I try importing this thing into unity.
But technically, the collar bone should also move up.
Quickly try to imitate the action with your shoulder- and see that the collar bone also moves upwards.
So the mesh around the shoulder area would have less distortion…
If that also doesnt work- u might have to check the topology.
Also- not quiet sure on this but- shape key driven animation would also work like someone suggested.
Right, I tried to do collar bone, but the one generated by the metarig doesn’t move at all, even with weight paints. So I tried subdividing the arm bone and using it like a collar bone, but all that does is make a really long arm with joints where it shouldn’t be. For example if I move the arm forward straight, the collar bone now points straight forward like the arm. I can’t find a way to make it so the collar bone moves a little with the arm, and the arm bone pivots around where the collar bone can’t bend too.
I’ve tried shape key drivers, but I don’t believe they import into VRChat and when I did try them, the inbetweens from arms down to arms up do a crazy deformed balloon thing.
I’ve looked up EVERYTHING having to do with shoulder, weight paint, collar bones, there is nothing and it seems collar bones on most peoples rigs are totally stationary. I’ve seen someones that was offset to the armbone and had some rotation, but there was no tutorial on how to do it.
Can you show what you’re trying? Screenshots etc…
You’d need to weight paint the collar bone. Rigify rigs will do this all for you. Have you tried using Rigify? Or is that not compatible for what you need it for?
Check this blend file and see how its done… i tried the shoulders they are perfect here
Yes, see here the collar bone from the metarig which is connected by an offset is weight painted but it doesn’t move at all. I’ve tried connecting this bone to the arm, but then it just acts as one long arm. I can’t make it so the collar bone only moves a little without restricting the rest of the arms movement.
I’ll download this and take a look. Though I’m not sure what to check for or how to apply it to mine. Let me have a look.
I’ve had a look. This shoulder does the same thing. Am I crazy or am I just interacting with the model completely wrong? I have inverse kinematics on and I grab the hand and then raise the arms up or I grab the upper arm bone and rotate it up.
This is how it look for me.
I hope someone else will weigh in on this matter, as i have no clue whats going on hehe
To get to this position it’s not the shouder that’s supposed to rotate, but forearm bones
You’re right. I was unfamiliar with the set up, I turned on kinematics and moved the arm, the collar bone does indeed move properly, but mine doesn’t. I don’t see anything in the settings that shows why this bone works that way. Keep in mind I’m extremely new and only just picked up blender a week ago. So hes got a collar bone, but its not offset, its connected to the upper arm, but doesn’t move as if its…a rope or a chain for example. How on earth do I create this bone?
But i suggest u re apply Armature Deform- with automatic weights.
Oops u said u are new… so u will have to delete all the vertex groups of the mesh before re applying… like this>
Check on a few tutorials on youtube- theres alot that can help u if u are new 
Would you say this looks correct?
The shoulders aren’t deformed, but there is clipping into the neck and head and the collar bones do bend parallel with the arms when extended fully.
looks alright to me, but cant see properly as the joints are in the way.
