How to make rain particles that react to the light in UE4?

Ninb

Arkham knight has the best rain effect I'v ever seen in any video game so far, it's a great example of what I'm asking for.

Calvinatorr

You can read the scene colour behind translucent materials, you could use this to intensify HDR values within the compressed range so emissive materials have more effect behind your particles

ilari

To add to what @Calvinatorr said, you could sample the scene color texture multiple times in a radial pattern and max/average them together to get a nice bloom effect, but you'd need lots of samples to make it smooth. The spiral blur node is good for quickly testing this effect, but in my experience it will kill your performance.

You might be able to get away with fewer samples by adding some noise to the individual scene color sampler's UVs, the result will look grainy and you can't use temporal AA dithering to improve the effect because the rain particles move fast.

A pretty cheap solution for this problem are spherical-ish normals to radially distort the image via refraction behind the raindrops with some added emissive boost. Somehow the refracted image even works with DoF. Example: https://www.artstation.com/artwork/VrGRg

Material settings:

Ninb

Thanks guys for the replies, I'll give it a try