I've been known to make characters that lack specific, anatomical shoulders. Shoot, I'm hard pressed to think of a character that I've built that actually HAS anatomical form and function to their shoulders. It's been a style choice on my part to not have them. (look at the blue guy in my short Lunch- no shoulders. Same with the other characters I've built over the years). So not modeling or rigging them in isn't necessarily an evil that must be purged from the land. It all depends on the style you're going for.
However, if you don't put the shoulders in, then you need to be prepared to animate your way around that limitation.
I'll offer an example. I've recently been watching & re-studying the 3 Wallace & Gromit films. Masterful animation. But Wallace's shoulders are pretty stiff. They don't rise or fall with any great regularity, in fact I doubt they move at all. The primary reason would be that building a stop-mo armature with movable shoulder angles would be a pretty nasty task to say the least. So while Wallace has anatomical shoulders in shape, they may as well not even exist for as little as they move in function. It would seem that Wallace is doomed to stiff portrayal of emotion. But anybody who watches the films knows that's not true.
So how do Nick Park and his team of animators get around this? The old magic trick known as inference, that's how. They use the angle of the upper arm to the elbows, along with the hand positions as strong, clear silhouette centric indicators of Wallace's feeling and from that the audience can infer the shoulder position that helps sell that idea. That classic Wallace pose, hands up, elbows out, fingers curled, palms forward- it's a great pose and it gets the idea across of the shoulders being up. When he's nervous or happy, he's got his hands up, giving the inferred impression that his shoulders are up. If you make that pose yourself right now sitting in your chair, you'll note that your shoulder's naturally are up. Viewers instinctively understand that in order to achieve that pose, your shoulders MUST be up (the key being the elbows out). So even while factually the shoulders on the Wallace puppet haven't moved, we're given the impression that they have moved. Which is fine, the arm angle and hand position tells us enough to infer that shoulder up feeling.
Now when Wallace is sad, Park's team keeps the arm angle downward, keeping the elbows in. The hands can be up or down, as they're not as important in the shoulder inference as the elbows in or out. But by using the technique of inferring the shoulder position by the arm angle, Park and crew are able to get the idea across about Wallace's shoulder movement without ever having to move them in reality. (again, for giggles, hold you hands up just in front of your collarbones in a classic Wallace pose. Now alternately move your elbows out or in, leaving your hands where they are in front of your collarbones. Notice how your shoulders go up or down to accomodate the new elbow angles?)
I studied that and employed the same technique myself with my shoulderless character in Lunch. Of course, some actions are absolutely precluded in such a set up (the hands low, elbows in, palms up shoulder shrug for instance.) But I've found that there's always more than one way to infer an emotion in your motion. Getting back to Park, he manages to animate his way around that limitation in Gromit by using his eyes, eyebrows and head motions. You get the same idea ("Wha? I dunno.") but with a different bit of movement. Heck, I'd argue that limitation (not being able to use the shoulders in an explicit shurgging motion) actually ADDS to the creativity and validity of the moment in the W&G world because it forces the animators to come up with a more creative way of expressing that thought without resorting to a cliche'd shrug.
Animation is all about trickery. Use whatever tricks are necessary to get the idea across. Literalism in form and function is NOT a pre-requisite to good animation (thank Heaven for that!). However, if you are going to stray from the conventions of anatomical form and function, you're gonna have to be aware of the limitations of that choice and be prepared to dodge the issue in a creative fashion. Personally, I enjoy the challenge.
-k
ps: and for the record, I hate rigging and skinning shoulders. The rigging folks tend to like that sort of stuff, but me, when it comes to making my own characters for my own projects- I'd rather not spend my time there. To each their own.
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