Hey guys, making a base character here. Everything seems fine in terms of deformation for the shoulder… but…
…When I rotate it in this way…
It gets kind of weird… Is it bone placement,topology mistake or do I need to paint manually to solve the issue?
You could probably weight paint that issue out rather easily. If you even looked at the manuel bastioni labs rigged characters they even have that similar deformation in the shoulder/armpit area in that pose as well. Only thing I can possibly think of is allowing for more topology under the armpit up over the shoulder/chest area to possibly allow for less movement during angular poses like shown.
Though it’s possible to force your arm forward like that, your shoulder would naturally also roll forward, which would relieve some of the pinching in that area.
Brian Tindall, formerly of Pixar, has a fantastic resource on topology for body articulation:
http://www.hippydrome.com/ArmsShldrRot.html
1 - Make the shoulder girdle 2 bones and at least have some rotation on the split close to the shoulder socket. Your arm does not just move like robot arm, there are alot of muscles and bones in tandem to get circular motion of an arm
2 - The arm bone actually does not rotate around the middle of the deltoid, it is closer to where the scapula and collar bone meets, try it (move your right arm up and put your left hand just above your right deltoid during the motion) . when the arm all the way up, it should make a dimp there
3 - Smooth the polygons around the shoulder a bit, also play around the direction of the edges.
