Particle Colission

Questions & Answers
1

Can a game object have collision with a particle effect ???

is it possible to ask after the number of particles in a selected area??

2

I can't help you with the second part but for collision detection, use a World Particle Collider.

3

As far as knowing the count of the particles: I think the only way would be to set the "min emission" and "max emission" to the same number, i.e. 100, set a large value for min and max energy and choose "One Shot". This way you will know that there are only 100 particles in the scene.

Sort of like the way "theOrbs" particle emitter in the Penelope tutorial are set-up. You don't need iPhone Unity (in case you don't have it) to open the Penelope project and view the scenes - but you will get errors due to the input differences, etc.

4

As to the second part of your problem, you could use a collider and count the number of things inside it with something like this:

public int Count = 0;

void OnTriggerEnter(Collider other)
{
     Count++;
}

void OnTriggerLeave(Collider other)
{
     Count--;
}

Just read the value of "Count" to get how many things are inside it. And, of course, as already mentioned, you use a World Particle Collider for the first part of your problem.