Help with making scratches/smudges in glass catch and spread light

Hi everyone!
I’m looking to create a glass material with either dirt or scratches that enhance the light behind it (in my case, the sun) but am at a bit of a loss if not using emissive (which of course then doesn’t give me the desired effect. I know that you can get things to get illuminated from behind with subsurface materials, but I’ve had no luck with this either. I’m not at a very advanced level with materials so the simpler the better :slight_smile:

Ref for what I’m looking to recreate-ish:

@ackehallgren you need decals :slight_smile:

There’s a massive amount in the megascans stuff which is now free to UE users:

( you have to login with your Epic ID )

Hey, thanks for the reply!
I already have textures, I’m trying to figure out how to make a texturemap catch the light and spread it (or at least fake it) like in the pictures.

Since currently translucent reflectance are affected by the opacity, you need to use your scratch texture in the opacity(to make those areas slightly more opaque than the bare glass) and then use it to increase roughness(more rough than the bare glass). You’re not going to be able to do the second image since Unreal natively doesn’t support anisotropic reflections, although there was a custom shading model floating around here at some point.Not sure if it supported translucency though.

I think I’m still not managing to communicate this correctly, sorry. No matter how much I change the roughness, since the window in my scene is facing away from the sun, it only gets cast in shadow, and I’d like for it to take the light (or just whatever is behind it) and amplify the brightness. Is this possible at all?

Left on the picture is what I have right now, right on the picture is a photoshop mockup that sort of shows what I’m looking for.

Try bloom with a world position offset for the bloom effect, if possible. Or alter the volumetric scattering intensity of the window in combination with the bloom that’s projected through it.