Making snow&rain "affect" some things?

[Mudbill]

The rain particle is, like all particles, not affected by physics. It's drawn to be a certain way. If you want it differently, you need to make your own.

One possible way might be to use many smaller particles instead. Not sure how that would affect the performance, but there are some droplet particles you might be able to use here and there, where the rain should be visible.