low poly to high poly workflow for character animation?

hi blender users!

what is the proper workflow for character animation, to set the low poly character and change to high poly
like this video, sintel, very low poly and after a full character??
how is the rigging process? you can use the same rig, and then when animation is ready update with the high poly character…but how you can do it in blender???


ohhh, thank you thank you, nice, to just one armature and 2 objects, 1 low 1 high poly, testing testing!