UDK 3 - Strange Glass Lighting

TheAxiom

Okay so the dirt on my windows, which are white on the translucent material, because if they're black then they become transparent, are being lit up in a bright yellow colour.

How can I get the dirt and glass to be realistic?

Obscura

Showing your material setup would help.

TheAxiom

Of course, sorry. Everything else is on default settings. I'm using a DominentDirectionalLight in the environment.

Obscura

To me it looks like it will be the specular because you don't have opacity map. It reflects green light from somewhere. You need an opacity map too in the opacity slot. It has to be whiteish where you want the dirt and where you want it to be opaque, and almost black, where you want it to be transparent.

TheAxiom

Oh believe me even with an opacity map the dirt just goes bright green.
The light in the my scene is white so it shouldn't be causing it.

Obscura

What's the environment color? Are you using lightmap specular? The tip about the opacity map was generic, a this kind of glass should be done this way. Because in the real life, its less transparent where it has the dirts. Including the dirts into your gloss map can also help to make it more believeable, just like with pbs.

TheAxiom

The environment colour is black by default I guess. I'm not sure about lightmap specular. This is my first time using UDK.

Obscura

You can check the lightmap specular thing in the material properties, but probably you use it because its enabled by default. I don't remember to how the environment color is by default, but I'm not sure about that its black. Maybe if you started from a totally blank scene, then yes, but if you started with a template then its not black. A scene post colorization can also cause the greenish color in your dirts, I would check that too. Thats all for now. Anyways, if you have a lot of green outside the building, then it can be the GI too. So there can be many reasons for this, and its a bit hard to tell what it is without having the scene in front of me.

JoakimMellergard

It might be unnecessary in UDK but it might be worth knowing that your specular values should not be higher than 1.0 (in your case the values are 0.0-5.0). Saturate it multiplied specular map before outputting it. I don't think this is related to your green dirt but still.

JoakimMellergard

Also, to make your glass more realistic you first of all need some reflections in there.

Vailias

Try backing off a few steps and just getting the initial colors set.

Turn off your opacity and specular and just get the diffuse in. See if its still green. Then work in the opacity, probably a map will do better than a straight number, since you have a lot of bits that are not transparent.

But speaking of green: The lighting on your bricks on the window is green also. Maybe these are related phenomena?