How to stop certain gameobjects from interacting with triggers

Question

I'm having a problem with my Item Pick up script where the trigger collider activates on every single gameobject it hits, this is a problem because it stops the player from picking up other game objects with this script. Is there anyway I can fix this or exclude certain game objects from activating the trigger?

My code:

 public class betterPickup : MonoBehaviour
 {
     
     public Transform player;
     public Transform playerCam;
     public float throwForce = 500;
     bool hasPlayer = false;
     bool beingCarried = false;
     private bool touchedWall = false;
    
     // Update is called once per frame
     void Update()
     {
         //checks the distance between the object being picked up and the player
         float dist = Vector3.Distance(gameObject.transform.position, player.position);  
         /*if the distance is less than 5 units, the object can be picked up, this is to stop the script from
         selecting of all game objects that use this script*/
         if(dist <= 5f)
         {
             hasPlayer = true; 
         }
         else
         {
             hasPlayer = false; 
         }
         if(hasPlayer && Input.GetKeyDown("e"))
         {
             //if the object can be picked up & the player presses E, the object is parented to the player camera
             //isKinematic is true so the game object doesn't fall down once picked up 
             GetComponent<Rigidbody>().isKinematic = true;
             transform.parent = playerCam;
             beingCarried = true; 
         }
         if (beingCarried)
         {
             if (touchedWall)
             {
                 //if the object touches a wall, the player stops carrying the object
                 GetComponent<Rigidbody>().isKinematic = false; 
                 transform.parent = null;
                 beingCarried = false;
                 touchedWall = false; 
             }
             if (Input.GetMouseButtonDown(0))
             {
                 //throwscript
                 
                 /*same as touchedWall except we add force to the object via playercam forward speed
                   multiplied by the throwForce so the object go fast*/
                 
                 //tldr: object go fast if left mouse do clicky clicky
                 GetComponent<Rigidbody>().isKinematic = false;
                 transform.parent = null;
                 beingCarried = false;
                 GetComponent<Rigidbody>().AddForce(playerCam.forward * throwForce);
             }
             else if (Input.GetMouseButtonDown(1))
             {
                 //drop script
                 //right mouse to drop object
                 GetComponent<Rigidbody>().isKinematic = false;
                 transform.parent = null;
                 beingCarried = false;
             }
         }
     }
     void OnTriggerEnter()
     {
         //if the object hits anything, it sets touchedWall to True 
         //trigger is used because disabling isKinematic also disables collision
         if (beingCarried)  
         {
             touchedWall = true;
         }
     }
 }

Answer 1

Best Answer

Answer by blinkafrootable · May 18, 2020 at 10:59 PM

There are two different ways that come to mind for me. The first is to assign layers to gameobjects and use Physics.IgnoreCollision() so that the layers that you don't want to set off triggers ignore each other. Another method you could use is to check the tag of the object that's causing the trigger. The OnTriggerEnter method actually has a parameter. You can write your OnTriggerEnter() method something like this:

     private void OnTriggerEnter(Collider other)
     {
         // if the object that's colliding/triggering doesn't have this tag, then run this code
         if (beingCarried && other.CompareTag("Your Tag") == false)
         {
             touchedWall = true;
         }
     }

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FudgePackingPro · May 18, 2020 at 11:23 PM 1

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Using Physics.IgnoreCollision() worked perfectly for what I was looking for, thanks!

blinkafrootable · May 19, 2020 at 12:19 AM 0

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Awesome, I'm glad that worked! Another tip for the future is that, if you don't like hard-coding the Physics.IgnoreCollision() functions, Unity also lets you edit which layers can collide from within the Unity Editor. Just go to Edit -> Project Settings -> Physics and then look at the Layer Collision $$anonymous$$atrix with all the checkmarks. Uncheck any boxes that you don't want collisions with.

How to stop certain gameobjects from interacting with triggers

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