Ragdoll On Collison

Questions & Answers
1

does anyone know how to make a object, when hit by another object change to another prefab which is a ragdoll?

2

There’s a good Unity tutorial, FPS Tutorial, which gives very interesting hints about dead replacement - you should download and study this tutorial, it’s really great and teaches many interesting game tricks.

Anyway, replacing an object by a dead version (dead replacement) depends on what the object is. The replacement of simple objects is easy: just instantiate the new object at the same position and with the same rotation, then delete the old one. If the object is a rigidbody, do it in OnCollisionEnter; if it’s a CharacterController, use OnControllerColliderHit:

var replacement: Transform;

function OnControllerColliderHit(hit: ControllerColliderHit){
  if (hit.gameObject.CompareTag("SomeTag")){ // if collided with the right object...
    // create replacement at same position and with same rotation:
    var dead: Transform = Instantiate(replacement, transform.position, transform.rotation);
    // destroy the original object:
    Destroy(gameObject);
  }
}

For objects that may have moving children, however, things are more complicated: after instantiating the ragdoll, you must copy position and rotation of each child. This is typically the case of animated characters: its ragdoll must have the same bones, with rigidbodies attached to some of them. In order to copy the children position/rotation, a recursive function is necessary:

var replacement: Transform;

function OnControllerColliderHit(hit: ControllerColliderHit){
  if (hit.gameObject.CompareTag("SomeTag")){ // if collided with the right object...
    // create replacement at same position and with same rotation:
    var dead: Transform = Instantiate(replacement, transform.position, transform.rotation);
    // copy position and rotation to the children recursively:
    CopyTransformsRecurse(transform, dead);
    // destroy the original object:
    Destroy(gameObject);
  }
}

static function CopyTransformsRecurse (src: Transform, dst: Transform) {
  dst.position = src.position;
  dst.rotation = src.rotation;
  dst.gameObject.active = src.gameObject.active;
  for (var child: Transform in dst) {
    // match the transform with the same name
    var curSrc = src.Find(child.name);
    if (curSrc) CopyTransformsRecurse(curSrc, child);
  }
}

See more info in the amazing FPS Tutorial.