Collision Detection without a RigidBody

Question

Hellow,

I'm using a OnTriggerEnter, but for some reasons.. It doesn't seem to detect the collision.

Used the method on other scripts, all work, but not for this particular one.

Here is the snippet of code

function OnTriggerEnter (other : Collider) {

  if (other.gameObject.GetComponent(Tagger).Meteor == true) {
     other.gameObject.GetComponent(MeteorMove).explode = true;
 }

EDIT

Saw it was because I missed that I needed the RigidBody. Is there a way to get a similar result as a OnTriggerEnter without a RigidBody?

Answer 1

Answer by skovacs1 · Oct 27, 2010 at 06:35 PM

I assume you are asking, "Why is this collision not being detected?" rather than something else about the undetected collision.

As per equalsequals' comment, it is possible that the collision is happening, but that your if statement or however you are identifying that the collision is happening is failing rather than the collision not being detected. Using Debug.Log and/or print statements would help you identify which is the case.

The docs on OnTriggerEnter clearly state:

Note that trigger events are only sent if one of the colliders also has a rigid body attached.

Do you have a Rigidbody or CharacterController on one of the colliders?

How fast is your object moving? It is possible that one collider is passing over the other without generating a collision. If this is the case, it would be better to adjust your scene, but if that is not feasible, then if you have a Rigidbody, you might consider changing your Rigidbody's collision detection to Continuous.

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Oninji · Oct 27, 2010 at 06:42 PM 0

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Just before you answered, saw the note in script reference. So my question would now be... How to achieve similar results without a RigidBody?

skovacs1 · Oct 27, 2010 at 07:03 PM 0

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If you do not have a Rigidbody or CharacterCollider, OnTriggerEnter() will not be called. If you cannot have one of those, then you will have to check for the collisions with either raycasts, spherecasts or capsulecasts in an update function of some variety.

tonydemot · Sep 18, 2012 at 03:22 PM 0

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you can always have a rigidbody without gravity have you tested that out if that's what you are looking for.

Answer 2

Answer by Jonas Planck · Oct 27, 2012 at 08:44 AM

I just spent a few hours banging my head against this problem... I found a solution by adding a rigidbody component, and opening the constraint dropdown of that component and checking all the boxes. This way, the object still collides with the trigger, but it's not at the mercy of physics, and it still obeys it's transform instructions.

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whydoidoit · Oct 27, 2012 at 08:45 AM 1

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You only have to set is$$anonymous$$inematic = true for the object not to be at the mercy of physics. See this unityGE$$anonymous$$S article for a discussion of how to make collisions and triggers work.

Jonas Planck · Oct 27, 2012 at 09:35 AM 0

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@whydoidoit: Thanks! This resource will come in very handy... I'm also new to scripting, so this will help me in ways I haven't even foreseen yet.

jbarbeau · Jun 30, 2015 at 01:01 AM -1

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Thanks JONAS, I had an invisible plane that I wanted to create an OnCollisionEvent. But I didn't want it to interact with the object passing through it. Your solution solved my problem, although I'm not sure if there is a processing penalty.

Collision Detection without a RigidBody

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