Ignore Collisions by Tag SOLVED!

I have been struggling with this for a while and I know a lot of people out there have too so now that I found a way to do it I thought I would share.

Well, the problem is simple: how can I avoid collisions between objects with a certain tag?

I tried collision managers, arrays of the objects that added themselves upon creation, etc. After a long journey I think I came up with a pretty simple and, sorry if I say so myself, elegant solution.

Imagine that you create 100 instances of an object with a tag "Robot" and you want them to collide with everything except themselves. Well, the only thing you have to add to the script attached to the robots is this:

Code (csharp):

1. function OnCollisionEnter (collision : Collision) {
2.  
3.     if (collision.gameObject.tag == "Robot") {
4.     Physics.IgnoreCollision(collision.collider, collider);
5.         }
6.  
7. }

And that's it!

The instant the robot touches another one it will add it's collider to the list of ignored collisions. Actually, this happens so fast that it won't even get to bounce.

This may be a primitive solution compared to the complex collision managers I've seen out there but I hope this helps someone. It's working perfectly for me.

Cheers!

 

Yeah, this works well enough in most cases. I used pretty much this exact method to get a S*** ton of rapid-fire projectiles to not collide with each other.

Of course, Unity 3 finally introduces layer-based collision management.

 

I wants. Right now!!!

'cause I have the same problem. I'm making a basically 2D shoot-em-up, but with 3D art. Things have DamageDealer and DamageTaker components. I want things to collide if and only if (objectA.DamageDealer.friendly != objectB.DamageTaker.friendly).

With most physics engines, you can assign mask bits and detect bits, such that you can easily set this up, but apparently not in Unity 2.6 :-(

Any other bright ideas would be much appreciated!

 

Wow, I completely forgot about tags! This gives me a great idea for a system I wanted to make...

 

Nice work dude, cheers!

 

Please don't dig out 18 month old threads ^^

 

huh? You would rather have him create a new one?

 

There was no point in posting anything. He didn't asked a new question or some clarification, basically just a "thanks" post, which bumped up an old thread and had no "added value".

 

A 'thank you' always adds value to a thread.
If it doesn't matter to who-ever is thanked, it matters to those who arrive later (when gauging whether this is sound advice).

 

And so the Battle Royale begins! Stay tuned for some riveting Germany vs Denmark action!

Update : Ok, looks like there's no further action on this front, fans are booing and lining up for their refunds.

Morale of the story : If you want to thank someone for an old post, thank them via personal message; it will avoid international incidents such as this one!

 

The morale of the story is to let people express their opinions of the answers.

 

The moral*

 

I'm in need of doing this for many objects but 2D. I'm finding a couple different answers but this one is interesting. Is it considered good practice to do this ignore right as it collides?

 

Hey man!! thanks for the info!! a six years ago...

 

thanks you.you helped a lot

 

2018 !!!!!

 

2019!!!!!

 

2019 thank you

 

Thanks to the OP this was super helpful

 

2019, Thank you!

 

This doesn't seem to work for me in 2019.2. My projectile collides first, then disables collisions. It won't hit any other colliders, but the first one stops it dead in its tracks.

 

waiting for 2020

 

Thanks, needed something simple for one collider, collision layering was too fancy.

 

Thanks!

 

It's now 2020, gotta love this thread, ten years old.

 

One more thanks from 2020!

Also, for others coming here from the future, it may be noted that disabling collisions using layers is really easy now.
Just make a layer for your type of objects (e.g. Projectile) and uncheck the Projectile-Projectile cell in the Layer Collision Matrix in the Project Settings > Physics panel.

See https://docs.unity3d.com/Manual/LayerBasedCollision.html.

 

Why is this thread still going now lmfao

 

Helped me lol too. Another bump I guess. But hey these bumps help google decide on whether or not it's still relevant, and well, it is.

 

2020, thank you

 

Such an informative thread lol. Thanks!

Is the manual Layer Based Collision mentioned by @jan_b based on this https://docs.unity3d.com/ScriptReference/Physics.IgnoreLayerCollision.html?

 

Almost 2021!

 

It seems elegant to me too.

 

I agree man. What a waste...

 

thank you!

 

Thank you very much

 

thank you

 

2021!