UDK Global illumination...no radiosity and light bounces

djoexe

Hi, I spent hours and hours to find out why I don't have any radiosity ( color bleeding) and any decent global illumination in the latest UDK package.

I tried every options coming from my dominant directionnal light and my world settings and I didn't find my answer.

The scene I want to achieve looks like this.


So there is only the light coming from outside that bounce everywhere in my corridor, noting else. Is there possible in UDK to achieve that kind of result with only 1 single dominant directionnal light ?

Thanks in advance

Ace-Angel

What exactly are you doing?

To achieve this effect, you typically need to bake out your Lightmaps.

WarrenM

Sure, it's possible to get close at least. Check your lightmass settings in your world properties. You can tweak things like diffuse boost and number of bounces.

Ged

I dont know for sure if this has any effect on things but is your object scaled well compared to the default udk player?

Zepic

...

djoexe

I'm not at home right now, so i can't post my UDK scene, but i'll post you guys what it looks like versus the image shown above.

osman

It's very possible to achieve results that are very close to that image. You just have to make sure that you're understanding the lighting and understand how to 'fake' it if you have to.

The type of lighting you see there is usually not even direct sunlight but just global illumination. In the rooms to the left, there are probably open windows that let in a lot of light. If you use area lights, you'll achieve the soft look you have in the image.

The way I do this in UDK is to create flat planes in the size of the windows and give them a simple emisive material.
Then turn on 'Use Emisive For Static Lighting' and it should behave as an area light.
Play with the following settings: 'Emissive Light Falloff Exponent' and 'Emmisive Light Explicit Influence Radius'. The second variable will only do something if it's not 0.

There's a lot more settings that you need to tweak, but I'm not able to do that at this moment, sorry. I can quickly list them here without any explanation:

Diffuse boost( either in your world setting or per material or per object )
Ambient Occlusion
Indirect Illumination Offclusion Fraction
Max Occlusion Distance
Static Lighting Level Scale( very important )
Num Indirect Lighting Bounces

Here are my test results from a while ago:



With a bit more work, it's possible to get very veyr close to the target image.

djoexe

I tweak those settings again and again and the only result that is more representative of what I want to achieve is when I add 3 point light. The problem is as soon as I bake the lighting...those nice fake Global illumination point light are overrided by my dominant directionnal light. So i'm not able to keep my setup that is the closest I got from my image for the lighting only.

Here are 3 shot taken from UDK. The first is the one with lighting baked, thats not the result I want. The second shot is the result I want to get but as soon as I bake...those lights disapered. The third shot is my world info setup.







Thanks again

Santewi

You shouldn't need those pointlights in the room. Have you tried increasing the indirect lighting scale in the dominant directional light's properties?

djoexe

Yes I did, but it only makes the scene lighter and washed wich I don't want. It seems that anything I do does't add radiosity to my scene, like a UDK limitation ?

Xendance

Well, no, you just gotta learn what settings are good. Does your map have a ligthmass importance volume in it btw?
Anyway, there just isn't a red button that magically does perfect radiosity baking. You gotta tweak the environmental colour, dominant light intensity, light indirect lighting scale, material lightmass overrides, material lightmass diffuse boost, actor specific diffuse boost and so on. There are loads of different parameters you can tweak.

djoexe

Yes I do have a lightmass importance volume n my scene, btw this just a test scene to get the lighting result I want. Is anybody of you could give me some settings and capture of what it looks like ? Because there is too much settings to just try everything and bake each time to see the result because it defer so much compare to the non-bake result...it will take days to find out.

Ace-Angel

How is someone supposed to know what your scene looks like to do tests? I mean are you using Decals? Placed instanced geometry? What is the resolution for each one of them for the lightmaps? Are you using Normals and Speculars or not?

And why are you asking people to do the work for you? That's just outright lazy! It's your scene, not mine or anyone elses, why should we put research on a very specific level, as well time, just so you can get a nice looking scene? It's your job! I mean you wouldn't ask a favor like this from someone in the studio you're working in, they would literally laugh in your face.

That's like saying you're good at modeling, when all you can do is sculpt and cannot even create a base-mesh!

Also, no it will not, a bake takes at most a couple of seconds for a scene like that. Put it on Preview and bake from there, it's not going to take bloody days, stop bollocking people.

Seriously, stop being lazy, there is no excuse. People tried to help you the best they can over the last 10 posts, now it's your turn.

djoexe

I'm not asking to do the work for me, I just ask for settings that I can compare with. But you're right, i'm a bit to specific. Sorry to anybody I bothered with this thread, i'm only here to learn you know. I'll be back with result...see you soon.

djoexe

I Finally find out that Dominant Directionnal light doesn't support color bleeding on its own, but point light does. I Change my dominant directionnal light to a Movable Directional Light and now my point lights that create my GI also provide color bleeding wich give me the result I was seeking for. Now it's time to place assets and build my scene ! So happy now

djoexe

Early look with fiew details, no dirt and such


And with a post process and AO Filter

Xendance

http://imgur.com/a/LjuLO

I put some example pics there what some of the lighting settings do. Hit the gear icon on the top right corner of each pic to view the full resolution picture.

Edit: Dominant directional light does support colour bleeding. Only thing it doesn't support is coloured translucent material transmission.

Jacky

Only movable and toggleable lights don't support GI as much as i know. You should be fine with a normal dominant directional.

djoexe

A little +3 hour of work looks like this...I will start to add drt on the ground soon.




I'll move my progress over my older thread wich was :

http://www.polycount.com/forum/showthread.php?t=107625

Xendance

Your meshes light up in a really weird way. As if they didn't have any lightmap UVs. Have you unwrapped the 2nd UV channel for lighting?

djoexe

as I mentioned above, I have some lightmap error to get fixed tonight. Also this is not an exterior scene so the light coming from outside is really bright to give me a better Global Illumination inside the corridor. If I do not set the light that bright, I wont get this luminosity and bloom coming from the light that strike the ground.

More update tonight if possible, see ya.