[UDK] Translucent Shadows

Visceral

Hello there Polycount, me again.

Im working on a scene (finally) and one of the main features of this dimly lit room is the color stained windows. Now, im working on a window shader that would allow me to have tranclucent colored shadows on the floor.

http://udn.epicgames.com/Three/Lightmass.html#Translucent%20shadows

However, i feel really stupid reading this article, i have no idea how my shader should look.

The amount of light passing through the material is called Transmission (different from TransmissionColor and TransmissionMask in the material editor, which operate on opaque materials), and ranges between 0 and 1 for each color channel. A value of 0 would be fully opaque, and a value of 1 would mean that the incident light passes through unaffected. There's no material input for Transmission, so currently it is derived from the other material inputs as follows:

Lit materials
BLEND_Translucent and BLEND_Additive: Transmission = Lerp(White, Diffuse, Opacity)
BLEND_Modulate: Transmission = Diffuse

I cant make any sense out of this? I understand i need to have my material on Blend_Tranclucent, But the rest is just gibberish.

[EDIT]

I havent done anything simmilar to this before, the closes i have come is by faking it with LightFunctions.

Herabek

The Transmission property allows you to control how much light passes through it with a 0 to one value for each color channel, so for red you can set it to 0 and only the blue and green light would transmit through (assuming they were above o) a value of one means that those color channels would not actually shadow, but simply pass through the object, so you could filter out specific channels and leave the rest alone... if you so desired for whatever reason.

Your material options there, BLEND_ Translucent and BLEND_additive take 3 linear interpolated inputs, while the BLEND_MODULATE only needs a diffuse.

I haven't played with this myself, but I presume that you could use BLEND_Modulate and get the desired effect but with less overall control. You could use an opacity map to cause the metal frame areas of your map to not allow any light to transmit, and or have sections of glass be thicker, or dirty, and transmit less light than other portions.

Visceral

Not sure i totally understand with "3linear interpolated inputs" where do theese guys go, and why?

Visceral

I think im getting it now, so i basicly have to mask out each channel with a lerp? That seems like alot of hazzle, just for this effect.