Question by Croolsby · Sep 20, 2015 at 07:51 AM · collision rigidbody kinematic freezeposition freezerotation

Rigidbody: Freeze All vs InKinematic

If you set a rigidbody to either kinematic or freeze all the position and rotation, it will be unaffected by physics. What are some other consequences freezing verses setting to kinematic?

I can think of one. A kinematic rigidbody will not send collision events, but a frozen one will.

This is the reason I am asking. I want to use the built-in collision detection, but I need to resolve the collision in non-realistic ways. So I want kinematic rigidbodies, but those don't send collision events, so I'm thinking of just freezing the position and rotation.

I'm wondering if there are some performance differences between the two.

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maccabbe · Sep 20, 2015 at 04:26 PM 0

Have you tried using OnTriggerEnter/OnTriggerExit/OnTriggerStay? Unlike OnCollision they can be used with kinematic rigidbodies.

http://docs.unity3d.com/ScriptReference/Collider.OnTriggerEnter.html

http://docs.unity3d.com/ScriptReference/Collider.OnTriggerExit.html

http://docs.unity3d.com/ScriptReference/Collider.OnTriggerStay.html

kaliAJ maccabbe · Jun 30, 2020 at 07:26 AM 0

@Croolsby I am experiencing something different here when I freeze the rotation without freezing position the collision event does happen. but when I froze them all(position, rotation) it just doesn't accept any collisions.

@maccabbe the triggers won't work since it needs one of the object set as a trigger, but not both. and since I have the prefab and I am instantiating a copy of the prefab and detecting the collision. this won't work.