Help Cloth collision actors

[domopuff]

Hello,

How can I obtain the actors that have collided with my cloth object?

Thanks!
Christopher

[josemendez]

Hello,

How can I obtain the actors that have collided with my cloth object?

Thanks!
Christopher

Hi!

You can get a list of all particle-particle contacts each frame by subscribing to solver.OnParticleCollision. Then it’s just a matter of retrieving the actor(s) involved in each contact. How to do this is explained in the manual: http://obi.virtualmethodstudio.com/manua...sions.html

Kind regards,

[domopuff]

Hi!

You can get a list of all particle-particle contacts each frame by subscribing to solver.OnParticleCollision. Then it’s just a matter of retrieving the actor(s) involved in each contact. How to do this is explained in the manual: http://obi.virtualmethodstudio.com/manua...sions.html

Kind regards,

Thanks for the reply! I managed to get the collisions detection working but performance did take a heavy hit. Any way we can try get the center points of a cloth instead?

[josemendez]

Thanks for the reply! I managed to get the collisions detection working but performance did take a heavy hit.

If you iterate trough all contacts in the main thread using a simple for loop and there's many contacts in your scene, performance will of course be less than good. Try doing this using jobs instead.

Any way we can try get the center points of a cloth instead?

Sure, iterate trough all particles in the cloth and calculate their center of mass. There's a snippet in the manual that does just this, pasting it here for convenience:
http://obi.virtualmethodstudio.com/manua...icles.html

Code:

using UnityEngine;
using Obi;

[RequireComponent(typeof(ObiActor))]
public class ActorCOM : MonoBehaviour {

    ObiActor actor;

    void Awake(){
        actor = GetComponent<ObiActor>();
    }

    void OnDrawGizmos(){

        if (actor == null || !actor.isLoaded)
            return;

        Gizmos.color = Color.red;
        Vector4 com = Vector4.zero;
        float massAccumulator = 0;

        // Iterate over all particles in an actor:
        for (int i = 0; i < actor.solverIndices.Length; ++i){

            // retrieve the particle index in the solver:
            int solverIndex = actor.solverIndices[i];

            // look up the inverse mass of this particle:
            float invMass = actor.solver.invMasses[solverIndex];

            // accumulate it:
            if (invMass > 0)
            {
                massAccumulator += 1.0f / invMass;
                com += actor.solver.positions[solverIndex] / invMass;
            }

        }

        com /= massAccumulator;
        Gizmos.DrawWireSphere(com,0.1f);
    }
}

Again, doing this in the main thread using a for loop will be slow. Note you can directly use Obi solver arrays in a job, see the "Using Jobs to process particles" section at the end of the page linked above.

kind regards,

[domopuff]

Thanks for your help. Managed to figure it out!