(05-09-2022, 01:40 PM)josemendez Wrote: Hi!

Your code doesn't make much sense: it iterates trough all contacts, and for all contacts against a collider in layer 7 (which I assume is the white cube in your image) it sets counter = solver.contactCount. So all your code is equivalent to just:

Code:

counter = solver.contactCount

Code:

void Solver_OnCollision(object sender, Obi.ObiSolver.ObiCollisionEventArgs e)
     {
         var world = ObiColliderWorld.GetInstance();

         // just iterate over all contacts in the current frame:
         foreach (Oni.Contact contact in e.contacts)
         {
             // if this one is an actual collision:
             if (contact.distance < 0.01)
             {
                 ObiColliderBase col = world.colliderHandles[contact.bodyB].owner;
                 if (col != null && col.gameObject.layer == 7)
                 {
                     counter++;
                 }
             }
         }

}

(05-09-2022, 01:49 PM)0hsyn1 Wrote: I was doing silly experiments I added the wrong code I added the wrong code.  Sorry  
counter runs but returns a number greater than 400 particles

(05-09-2022, 01:51 PM)josemendez Wrote: Yes, as I explained this will add one to the counter every frame a particle is in contact with the collider. So unless particles are only in contact for one frame (which is highly unlikely), it will return a number far greater than 400.

What you want is to determine if a particle has already been counted and if so, ignore it. There's many ways to do this, easiest is to use a hash set. See:
http://obi.virtualmethodstudio.com/forum/showthread.php?tid=708&highlight=collision

(05-09-2022, 01:58 PM)0hsyn1 Wrote: Yes, I found the post you shared while doing research.
"idToCollider" "particle"  syntaxes appear as console errors.

(05-09-2022, 02:06 PM)josemendez Wrote: That code was written for Obi 3.5, idToParticle no longer exists. You get the collider like you were already doing in your original code:

Code:

ObiColliderBase col = world.colliderHandles[contact.bodyB].owner;

However the idea of the code is still perfectly valid: use a hash set to determine which particles have already been counted.

I've modified your code to work properly:

Code:

[RequireComponent(typeof(ObiSolver))]
public class CollisionCounter : MonoBehaviour {

    ObiSolver solver;
    [SerializeField] int counter = 0;

    HashSet<int> particles = new HashSet<int>();

    void Awake(){
        solver = GetComponent<Obi.ObiSolver>();
    }

    void OnEnable () {
        solver.OnCollision += Solver_OnCollision;
    }

    void OnDisable(){
        solver.OnCollision -= Solver_OnCollision;
    }
   
    void Solver_OnCollision (object sender, Obi.ObiSolver.ObiCollisionEventArgs e)
    {
        HashSet<int> currentParticles = new HashSet<int>();

        var world = ObiColliderWorld.GetInstance();

        // just iterate over all contacts in the current frame:
        foreach (Oni.Contact contact in e.contacts)
        {
            // if this one is an actual collision:
            if (contact.distance < 0.01)
            {
                ObiColliderBase col = world.colliderHandles[contact.bodyB].owner;
                if (col != null && col.gameObject.layer == 7)
                {
                    currentParticles.Add(contact.bodyA);
                }
            }
        }

        particles.ExceptWith(currentParticles);
        counter += particles.Count;
        particles = currentParticles;
    }

}