instance colliding

Unity Engine
1

I’m making an RTS game where you build towers, and I want to not let the player build a tower when the position he will build the tower already has a tower. I added a collision box and layers for this, but it seems like I need a rigidbody to trigger the collisions… and adding rigidbody messes it up because when the towers collide they just throw away eachother into space.

How can I implement collisions using collision boxes components without a rigidbody?

2

You could do a raycast where you want to place the new tower.

Or you could have a rigidbody on the new tower that you want to place, and then it will register collisions with existing towers, and then destroy the rigidbody after it’s successfully placed in position.

3

Thanks, raycasting works!

but how can I make raycast not check for collision with itself? I mean it’s always checking a collision with itself

here’s my codes:

void CheckCollisions(){
        Vector3 pos = Vector3.zero;
        RaycastHit hit;
        collidingwithothertower = true;
        if (Physics.Raycast (transform.position+Vector3.up,-Vector3.up,out hit,5.0f)) {
            if (hit.transform.position != transform.position) {//don't collide if they are both the same object
                collidingwithothertower = true;
                Debug.Log ("Collision found");
            }
        }

    }

tryed adding the if (hit.transform.position != transform.position) {//don’t collide if they are both the same object

but it now doesn’t detect any collisions

4

You could have new towers on the IgnoreRaycast layer, and once placed change them to a different layer.

5

I searched around and found that I can detect all collisions instead of stopping at the first one:

void CheckCollisions(){
        Vector3 pos = Vector3.zero;
        RaycastHit[] hits;
        collidingwithothertower = false;
        hits = Physics.RaycastAll (transform.position+Vector3.up*2,-Vector3.up,5.0f);
        foreach(var hit in hits){
            if(hit.transform.position != transform.position){
                collidingwithothertower = true;
                Debug.Log ("Collision found");
                Debug.Log (hit.transform.name);
            }
        }
    }

thanks for the help!