Remove a particle on particle collision

Unity Engine
1

Hello,

I have a case where by I want to draw on a texture when a particle hits a given collider.
I have this working, however the particle bounces on the collider then hits again at another point.
What I want to do is delete the particle when it hits a given collider.

I can get the particle collision events, but this does not give me the particle object so I can’t remove it from the particle systems particles array.

Does anyone have any ideas on how I could achieve this.

Thanks,
Sam.

2

Unity - Manual: Collision module Set the lifetime loss greater than its max lifetime. If that makes sense :stuck_out_tongue:

3

But how do I know which particle it is?
If the particle collides with a floor for example, I still want it to bounce. If the particle collides with a certain object, I want the particle to be destroyed.

Sam.

4

Hello, I’m kinda late, but here it is:

public class ParticleCollider : MonoBehaviour
{
    private void OnParticleCollision(GameObject other)
    {
        List<ParticleCollisionEvent> events;
        events = new List<ParticleCollisionEvent>();

        ParticleSystem m_System = other.GetComponent<ParticleSystem>();

        ParticleSystem.Particle[] m_Particles;
        m_Particles = new ParticleSystem.Particle[m_System.main.maxParticles];

        ParticlePhysicsExtensions.GetCollisionEvents(other.GetComponent<ParticleSystem>(), gameObject, events);
        foreach(ParticleCollisionEvent coll in events)
        {
            if(coll.intersection!=Vector3.zero)
            {
                int numParticlesAlive = m_System.GetParticles(m_Particles);

                // Check only the particles that are alive
                for (int i = 0; i < numParticlesAlive; i++)
                {
                  
                    //If the collision was close enough to the particle position, destroy it
                    if (Vector3.Magnitude(m_Particles[i].position - coll.intersection) < 0.05f)
                    {
                        m_Particles[i].remainingLifetime = -1; //Kills the particle
                        m_System.SetParticles(m_Particles); // Update particle system
                        break;
                    }
                }
            }
        }      
    }
}

Use it on the object that has the collider.
Remember to check Send Collision Messages on Collision module of the particle system object.

1 Like
5

thank you [luuchowl]( Remove a particle on particle collision members/luuchowl.1120072/) for sharing the code!

6

Why not just use the built-in “Min Kill Speed” and “Max Kill Speed” in the Collision section of the particle system to kill the particles on Collision?

4 Likes
7

In the previous example by luuchowl you would need to not create a new instance of the particles array (m_Particles) each collision. You want to have a variable in your instance to hold that data to avoid constant memory reallocation.

To solve this, I used the collision “lifetime loss” property which by default is set to 0. But you can set it to 1 for the particles lifetime to be maxed out on the collision so it disappears. Or you set to 0.1 for it to lost 10% on the collision, which may be more interesting. But this is absolutely the way to make a particle disappear on collision.

2 Likes
8

too late but I solved that problem by setting: particle sys > sollision => Min kill speed = 1000 (this is infinite number in my case), Max kill speed = 0 (this is min speed in my case)