Are shape keys commonly used for elbows/knees?

Is it common to correct our poses with shape keys on hard zones? Like elbows, knees ecc. In low poly models it seems that rigging sucks a bit, so I am thinking to shape keys. Is it professional to do?
And what about contracted muscles? Shape keys here too?
I know that i -can- use them, but I want to understand if it is common and professional, or if it isn’t suggested to do.

(And, finishing: can shape keys be exported for Unity/UE4?)


Most people do this, yes, and then drive the shapekey with values such as bone rotation, etc. High end productions with developers and experienced riggers on board use their own solutions usually, muscles if the project is kinda realistic, otherwise not necessarily. But us, mere mortals, use shapekeys. You can try this addon too :

Oh thank you very much! I’ll try it!
But anyway I was talking about elbows and knees especially (that are not muscles) and when they’re bent sometimes we obtain too “curved” elobows/knees. So I don’t know if it was professional to adjust them with shape keys or with a better weight paint if possible. In low poly models it is difficult…
Anyway nice addon.

Yeah the more resolution the better, but also more difficult to correct.