Hi!
I have rain partical system effect with type GPU sprites. Collision is set to Bounce in partical system. The particals bounce off opaque materials perfectly, on the other hand I have translucent glass material and the particals penetrate through the glass. How can I avoid this?
Thanks!
It can’t, the collision is based on the depth buffer, and translucent materials aren’t added to the depth buffer. Sorry 
Distance Field as Collision Mode will fix this? If yes, I don’t know the idea. Is there a tutorial on that?
Basically Distance Field could fix it. Another idea would be stochastic transparency. But could you explain your current use case first?
The rain is in front of the car and it is slightly rotated towards the windshield. The windshield’s material is translucent. So the rain particals penetrate in to car. That’s my case. Thanks!
This should’t be too hard to solve if you are willing to modify default shaders. You could aproximate windshield with single quad and then test collision against that quad for every particles. You should modify this shader and somehow pass the windshield quad+ transformation there.
https://github.com/EpicGames/UnrealEngine/blob/master/Engine/Shaders/ParticleSimulationShader.usf