Fluid Counter

[0hsyn1]

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;
    }

}

works perfectly, thank you very much