rain on a plane?

yo people I would like simulate rain by creating short sigments of lines that will disburse when they hit a invisible plane. The back ground will be white and I will be rotating the camera. Now I don’t have any trouble rotating the camera angle but I would like know what formula do I use and how to I use it to find out when I point is on a plane.

Hi, I did something like that before, but I used a different approach. Particle engines work nicely, but there is probably better ways. But basically, with a particle engine, you can just test for a collision between the particle and the plane and have it burst into smaller droplets.

Old GLman