Particle Escapes Collider

I have a mesh collider on a tube object (to simulate a pipe). The particle emitter is cone shaped and inside one end of the pipe. The particles bounce around and move along inside the pipe… this works well.

But then imagine a box-like object that pushes down through the middle of the pipe. This box-like object has a mesh collider on it. When the box moves into the pipe, the particles are blocked from moving along the pipe and the particles stay on one side. This works pretty well.

But… there are a couple of renegade particles that sometimes will escape the gate or the pipe itself.

Is there a method to make sure no particles ever escape the pipe or get past the gate?


There is a property on the Collision Module of the emitter called Collision Quality. crank that up and it might resolve it.

Here is a screengrab illustrating the problem.

The collision quality is on high. There is an invisible tube-like object with mesh collider defining the inside dimension of the pipe and a box collider on the box object. The particles should be staying inside the pipe collider and bouncing off the box with no escapees.

What else can be done to make particles work properly in Unity Pro? Should my invisible mesh collider object have a more dense mesh?

Thanks for any ideas!