I'm rigging up some characters for a uni project and theres something i'm wondering. I've read many tutorials explaining ik/fk switching for arm animation. They all seem to involve creating 3 different arms, an ik, an fk and the real one. You then you use set driven keys to control the weighting of the fk and the ik arm to the real arm. I've done this in the past, and it seems like a fairly standard thing. However seeing as the weighting of the ik handle can be keyed using the ik Blend attribute on the ik handle, is there actually any need for the 3 duplicate arms and driven keys set up?

I know that the 3 arm setup is used by a lot of people, so i'm guessing it must have some merit right? If i simply use one arm, and switch between ik/fk using the ik blend attribute will this cause any issues later on. I've tested switching between the fk/ik. It seems to work fine. Anyways just wondering whats the deal?