How reliable is particle collision?


I’m using the legacy particles with a world particle collider and I’m wondering if A)The collision is accurate or B) I’m doing it wrong.

I have a sphere object which is a placeholder for my enemy; on the sphere I have attached a rigidbody,sphere collider and the enemy script. When the enemy is enabled it simply moves towards the player using this line of code in the Update() method :

		Vector3 pos = (transform.position - player.transform.position).normalized;			// Get the direction to move
		transform.Translate(-pos * speed * Time.deltaTime);	

I tried using doing it with AddForce in FixedUpdate() and got some very strange results with seemingly random moving objects.

The particle emitter is instantiated (That’s the only way I could get it to work, can I not use the Emit() method?) in when the player clicks to shoot and spawns only 1 particle. The size of the particle is 3, it just wouldn’t collide with the sphere gameobject at smaller sizes. If a particle hits the enemy it calls the OnParticleCollision() method which calls another method within the enemy script and destroys the enemy. As the game progresses the speed of the enemies increase and eventually it gets to a point where the particle simply goes straight through the sphere.

I set the enemy rigidbody to interpolate and collision detection to continuous dynamic and noticed no change really.

I know this covers a few questions, but they are all related for my project and I’ve spent quite a bit time searching with no solid answers.

What I would like to know

  • Is there a better way to move my enemies?
  • Should I use the old particle system or can this be done with the shuriken system?
  • Am I using the correct methods to detect the collision or what is the best way for fast moving objects?
  • Can this be done with AddForce()? I thought this gave a smoother looking movement.
  • I tried using raycast to detect the collision, but found it very difficult to make it look like the bullet effect hit the enemy before it was destroyed.

Moving with transform.Translate messes up physics. It’s like dragging it yourself in Scene mode while the game plays. It sort of works if you move less than the collision error – the physics step will notice and will push them apart.

The particle colliders are mostly just for special effects. It’s, as best I know, not full-blown collision, with all the time that would take. Best way to fire a “particle” at something is to fire a regular rigidbody + collider, then attach (child?) a particleSystem to that. Then you can adjust the invisible collider to be as big as you need.