Got a pretty good snow simulation going now, added some mist too, thanks for all the help.

Iain, GatorHex like what you been doing here, I change one line from make box to make sphere



gives it a diffrent look when falling, just wondering how would you get this to pile snow up on top of an object?

The snow/rain gets reused when it hits the floor.

I wouldn't recommend letting it pile up and stay on screen because you would end up with thousands of objects on screen which would cause your computer to get slower and slower until it froze.

My recomendation would be to use a flat plain and draw a snowflake on it with transparent backgound to make it look more real.

[UPDATE]
It's worth looking at this code if you want a non shader bullet tracer effect.