If there is no collision...

Hello Everyone,
I am wondering about Non-Collision actions. Like, if there is no collision, a action could be played. But if there is collision, that action can not be played at that time. I have researched online and the closest thing i have seen is "OnCollisionExit" which happens if you leave the collision of a object.
Is it possible to make this possible?

 

Can you describe more what you're trying to accomplish?

What event are you trying to trigger some action from? If you just want to do something every frame as long as your object is not colliding with anything, you could do something like this:

Code (CSharp):

1. HashSet<Collider> currentlyTouching = new HashSet<Collider>();
2.  
3. void OnCollisionEnter(Collision c) {
4.   currentlyTouching.Add(c.collider);
5. }
6.  
7. void OnCollisionExit(Collision c) {
8.   currentlyTouching.Remove(c.collider);
9. }
10.  
11. void Update() {
12.   if (currentlyTouching.Count > 0) {
13.     // This code will run if you are touching at least one object    
14.     Debug.Log("I'm currently touching " + currentlyTouching.Count + " objects!");
15.   }
16.   else {
17.     // This code will run when you are NOT touching ANYTHING.
18.     Debug.Log("I'm not touching anything!");
19.   }
20. }

 

In my game, i am making a building system where you can place stuff and etc. This post is helping me with a over-lapping problem i am having where you can place blocks inside of each other. So i wanted to create a script so the block can be placed IF there is no collision but if there is, the block can not be placed

 

I have tested the script but it has 4 errors mainly saying Collider has no definition for (Add, Remove, Count)

 

If you're talking about placing blocks it might make more sense to use a test like Physics.CheckBox to see if anything overlaps a given box:

https://docs.unity3d.com/ScriptReference/Physics.CheckBox.html

 

You must have mis-copied this line then:

Code (CSharp):

1. HashSet<Collider> currentlyTouching = new HashSet<Collider>();

 

They aren't really blocks, I am using prefabs of buildings/trees/other stuff

 

Unrelated note, is there any way to stop box colliders being solid? (I can't test it, i added a box colldier to the "Building things" and set them to trigger but they are just acting normal)

 

Exactly as you noted, set the Collider as a trigger. If you do that you'll have to use OnTriggerEnter/Exit etc. instead on OnCollisionEnter etc. in your scripts.