Lighting issues

lpcstr

Ok, so for my fist question. What the heck is going on here and how do I stop it?


http://img593.imageshack.us/img593/1781/26875333.jpg

I've got one light here, for which I have disabled static shadowing. I've also enabled bForceNoPrecomputedLighting. At low angles, it looks like rubbish. If I build the lighting, it goes away. However, I don't want to build lighting, because I want to be using dynamic lighting only. This brings me to my second question.

How do I completely disable static lighting in a level?

Oniram

i dont know why you wouldnt want to build lighting.. lightmass does amazing things for you. im not sure if there is a way to get that banding to go away, as lights are intended to be built (otherwise it creates HUGE performance issues).

lpcstr

Oniram wrote: »

lightmass does amazing things for you.

No, really it doesn't.

Light maps are only good for static scenes, my scene is fully dynamic. Get the idea?

Xendance

That's shadowmap acne. It's an inherent problem with shadow mapping tech, there are ways to mitigate it but I don't think you can do any of that in UDK.

Ace-Angel

Less extreme the angle, the less acne should show up. Avoid 80-90* angles and aim for more diagonal ones.

Also, try playing with Light Cone, it's under the Properties for the Light.

Oniram

lpcstr wrote: »

No, really it doesn't.

Light maps are only good for static scenes, my scene is fully dynamic. Get the idea?

if you want fully dynamic/realtime.. why not just use cryengine. what sort of scene are you going for that requires all lights to be dynamic?

System

Try lifting the light from intersecting with the floor mesh.
Also I have to say +1 to Oniram.
Lightmass is built to create efficient and usable lightmass combined with specific statics or areas that are lit dynamically.

Try using movable light actors which are default dynamic.

lpcstr

Ace-Angel wrote: »

Less extreme the angle, the less acne should show up. Avoid 80-90* angles and aim for more diagonal ones.

Really? Because it starts becoming horribly noticeable at as little as 60 degrees.

It seems to me that dynamic lighting and UDK just don't mix.

Ace-Angel

That's strange, although in retrospect, all of my assets are mesh and not BSP, so that might add to the equation with explicit normal, etc. Did you try and see if Mesh assets have the same issue?

Also, I remember some guy on UDK forums mentioned that the acne and banding where a quick RT solution Epic implemented for the average user, and that changing a set of values and their numbers would solve this issue.

However, it was changing a number in the .INI files, and I cannot for the life of me find that post again, it pretty much was the holy grail for shadow solution, and the guy even posted on how you could get upto 4K RT shadows if your PC could handle it.

I will look up again and see if I can find anything shedding light on this (pun intended).

Some more info:

http://www.polycount.com/forum/showthread.php?t=91047
http://www.polycount.com/forum/showthread.php?t=76977

http://forums.epicgames.com/threads/743817-These-Effin-Dynamic-Shadows!?
http://forums.epicgames.com/threads/721755-udk-shadow-problem/page2

http://translate.google.com/translate?sl=de&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.unrealed.info%2Fforum%2Fshowthread.php%3F9440-Shadow-Acne-Artefakte-reduzieren

http://forums.obsidian.net/index.php?showtopic=55422

System

world info -> lightmass -> force no precomputed lights. build lighting once. and use movable lights with dynamic shadows.

LoTekK

Does udk have a setting for shadow bias? At low angles, that sort of shimmering is inherent, but you can avoid it by raising the bias. This introduces another problem where shadows "start" a little past the shadow occluding object, but it's a lesser evil than shimmering

Xendance

LoTekK wrote: »

Does udk have a setting for shadow bias? At low angles, that sort of shimmering is inherent, but you can avoid it by raising the bias. This introduces another problem where shadows "start" a little past the shadow occluding object, but it's a lesser evil than shimmering

In UDKEngine.ini find ShadowDepthBias.

HAWK12HT

Well I think it dont work with Ini either as i have tried it myself. This issue is also known as "Z fighting" , try putting two meshes and intersect them around half way you ll notice something like this shadow issue but with polys.
As someone mentioned Epic put this for a reason, quick workflow. There is no way to avoid it even EPIC's Night and Day demo map is full with Z fighting (acne) issue. They have covered it with lots of grass, huge Rock chunks and have engineered the level in a way that player only sees the nice quality areas . Thats why you have to make ton loads of detailed meshes for your environments to fill the screen thus effectively reducing this problem.

Now the most importan bit, I saved it for last Increas you Dominant Light >properties> Cascading Shadow Radius to around 2500 to 3500, and the values below to 3 / 4 or 4/ 4< this you have to try as it kinda works like on the overall scale of your scene.

Hope it helps