"Shoulders... Bloody shoulders... They never ever ever look right, I don't know how people do it."
The biggest tip I have for animating shoulders is make sure to make moveable collarbones. By that I mean, instead of having the shoulder attach directly to the spine, have another joint very close to the spine in the hierarchy between the spine and shoulder. This extra joint is the clavicle/collarbone.
I don't know why but no learning resources (teachers, books, websites, whatever) ever seem to mention how crucial the clavicles are for animating the shoulders, but they are vital. It only makes sense really, since you want your skeletal rig to mimic reality, and in reality the collarbones move on joints. The joints of your clavicles are what allow you to shrug your shoulders; your arms don't raise at all but your shoulders are moving up and down quite a bit.
Thus when you animate arms raised you only actually want to rotate the shoulder joints to pointing the arms 45 degrees up. The rest of the arms-up rotation comes from the collarbones. This will pull the shoulders in toward the head and achieve a natural deformation.
The biggest tip I have for animating shoulders is make sure to make moveable collarbones. By that I mean, instead of having the shoulder attach directly to the spine, have another joint very close to the spine in the hierarchy between the spine and shoulder. This extra joint is the clavicle/collarbone.
I don't know why but no learning resources (teachers, books, websites, whatever) ever seem to mention how crucial the clavicles are for animating the shoulders, but they are vital. It only makes sense really, since you want your skeletal rig to mimic reality, and in reality the collarbones move on joints. The joints of your clavicles are what allow you to shrug your shoulders; your arms don't raise at all but your shoulders are moving up and down quite a bit.
Thus when you animate arms raised you only actually want to rotate the shoulder joints to pointing the arms 45 degrees up. The rest of the arms-up rotation comes from the collarbones. This will pull the shoulders in toward the head and achieve a natural deformation.