2D collision detection without rigid body?

[Muhwu]

I have a simple game where I require a certain amount of collision detection from my models. However, I do not need physics in this so the checks are actually mostly just box checks or shape checks which need to trigger an event.

I got it to work using RigidBody2D + BoxCollider2D on the colliding object and BoxCollider2D (With isTrigger set to true) on the other one.

I do my translations currently using translate rather than physics (Time will tell whether I will do it like this in the end as well).

So my question is that is there a way to clip the Rigid Body out of the whole equation. I feel like the current model is a bit silly given that I have a Fixed Angle rigid body (All game characters will be like this and there might be many so this creates overhead?) objects with all the variables set to 0.

[JiajieXu]

The answer of Spinnernicholas is not correct!

You need at least one rigidbody2D attached in the collision of two colliders.

To improve the performance is a good practice attaching the rigidbody2D to the moving gameobject, and leave the static collider without rigidbody.

some useful links are:

• 2D Physics - Unity Learn
• Unity - Manual: Rigidbody 2D

[DiegoGomez87]

Hi, Maybe this is not the best approach and probably you are not expecting this answer anymore, but someone like me could reach this thread and this could be useful for him:
If you add a rigidbody with “Is Kinematic” = true and set the box collider with “Is Trigger” = true
you can detect collision using the following code:

void OnTriggerEnter2D(Collider2D other) {
}

Hope this help

[D00zy]

The solution I found was adding a rigid body and freezing x, y and rotation,the solution I found was to just add a rigid body and freeze rotation, x and y

[Spinnernicholas]

Yeah, you can drop the rigidbody and just do everything with colliders. Then you can respond to events OnTriggerEnter2D, OnTriggerStay2D, and OnTriggerexit2D.