Hi,
I have sword in my game and when user attack my humanoid animated model with sword i want cut body parts with sword.For example if attack to head /hand i want cut it and drop it to ground.How can i do this ? I read something about cutting mesh but it looks hard for complex models.
I think i can make it with giving rigitbody to my body parts.My models from mixamo and it doest have separate body parts.How can i make parts separate ?
just stumbled across your question, looking for the reason why my mixamo-chars are totally destroyed
theres no easy way to do it 
youd have to create a new rigged-mesh for each lost bodypart
then exchange the mesh triggered through colliders of the bodyparts.
here you have to have a mesh for all possibilities!!!
instanciate through the collision, the cutoff bodypart and give it a rigidbody to let it drop
hope htis helos, or did you find a solution