Whew, been a long time since I posted!
So I'm setting up some rooftop deflectors, and particles are emitting from something running around on the roof. Like debris being kicked up from the roof. The roof is really slanted, and I have gravity in there, of course. I have friction on the deflector. However, a setting of 99.999 still lets the particles slide too much, and 100 stops them completely. Any ideas on how I can get something in between?
You could try a Drag space warp and see if that gets you where you want. Otherwise maybe Speed By Surface on a plane, and do some trickery to get the speed as the inverse of the previous speed.