why use axis-angle to represent rotation

[ffiioonnaa]

Hi, I have a question that why smpl choose axis-angle representation? Cause I find I can't rotate the part to a position that I want by giving angles, why don't use euler angle?

[longbowzhang]

I guess what you would like to achieve is reffered to as inverse kinematics, basically from positions to the joints angles.
I suppose it has nothing to which representation one uses for the rotation