assuming the arms would be solid, the rendering engine should be able to judge the depth of each polygon that makes up the arm, and render it accordingly. however, if you were to use alpha transparency, yes they''d have to be rendered from back to front because if you rendered from front to back, you may not see the polygons in the back because the depth of the front polygon has already been judged as being in front of the one in the back. if you disabled the depth test, then the back polygon would then be rendered on the front one and it would look all screwy.