Light through Alpha not casting correct shadows

salacious_Crumb

I'm still a bit new to UDK. So much info and settings it is overwhelming.
I've tried looking for a solution but can't seem to find one.

The problem is Lighting. I'm casting a light through a static mesh which has an alpha, basically light coming through a window. But the alpha isn't casting shadows correctly.
Things I've tried:
-I have second UV sets for light maps
-They dont overlap, etc
-I have the light map set up high 1024
-its double sided (obviously)
-the texture is a 1024 tga with alpha (should be enough res in that!)
-light SFQ is high

here are some pics. not sure what other information you need.

Oh, I'm also getting light 'bleeding' out at the bottom of the wall. I've checked the static mesh and it defintely intersects the floor, so theres no gap. Is there anyway to stop this?

Oniram

i had this issue recently. fix i found for it was 2 things.

1. i had to actually create a second face on the backside. the "Two Sided" setting just wasnt working for me so i put 2 faces almost on top of each other and that got the general alpha going.

2. if you are using a bsp for your floor (it looks like it), hit f5 on the surface and lower the lightmap resolution to something like 2 4 or 8 (1 or 2 will give best results)

Lamont

Alpha has to be masked.

Arac

Just increase (or decrease if it's BSP) the lightmap resolution of your floor. This will also stop the bleeding.

But to get that kind of detail in your shadows, you'll need a huge lightmap.

A. Rabbit

Lamont wrote: »

Alpha has to be masked.

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

Lamont

A. Rabbit wrote: »

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

If it's a latticed window, the lattice are made of a solid material (looks like wood), so it was recommended to be set to mask, which would allow the shadows to use dynamic lights.

Snader

I'd say add some extra polygons a couple of inches on the outside of the wall. Give the wall actual thickness. Right now it looks like you've only got the visible parts modeled.

salacious_Crumb

Thanks for the replys. It was the BSP lightmap res.
I ended up using a static mesh floor and upping the lightmap res on that.
Two sided seems to work ok for me, didn't need to create second faces.

You're right about the lightmap resolution having to be stupidly high though!
Is there anyway to blur the shadow's edges so I don't see the aliasing so badly?

Habboi

For shadow settings are you using modulate or modulate better? One of those makes it better I hear and no, it might not be the modulate better one

salacious_Crumb

Heres how the lightings looking now. Just want to soften the shadow slightly and move on. (if i were using maya then i would be changing the light angle under the directional light to get softer shadow edges).

I will try the modulate/modulate better next

Xendance

salacious_Crumb wrote: »

Heres how the lightings looking now. Just want to soften the shadow slightly and move on. (if i were using maya then i would be changing the light angle under the directional light to get softer shadow edges).

I will try the modulate/modulate better next

Well, the setting name is almost the same as in Maya then. Select your dominant directional light, go to it's properties, and there under light component (or something similar) should be a tab called "lightmass". In there should be a setting called "light source angle". Increase that to get blurrier shadows.