Texture/Shadow Distance Error

Yuke

Hi all,

I'm starting up a new project in UDK as I've never created an environment within it using my own models etc.

I created my basic modular building pieces and threw them into UDK with 2 UV channels for the textures and lightmaps.. however I'm getting some very weird errors that occur when I move away from the objects.

When I'm close to an object everything looks ok, however the further away I get from it the more distorted the shadows get and even more noticably the more distorted the textures get.

I thought it might be something to do with LOD or culling but I can't seem to figure out how to fix it.. Here's some screenshots to show what I'm on about, thanks very much for your time!

From a distance with the obvious problems circled:


Still present when I get a bit closer:


Clears up when I'm right next to the mode:

Jacky

Have you tried it after building your lights?

Yuke

This is after lighting has been built (just 1 dominant directional)

Jacky

Hmm, i've had this issue with dominant directional before but it was either because lighting wasn't built or because of the angle of the light. Not sure what may be causing yours.

JamesWild

This problem might be caused by outdated graphics drivers, I've seen that happen once before, if it can't be fixed by angling the light a bit more.

praetus

If I'm not mistaken this is a common problem when your texture is heavily repeating. The further away you get the texture has trouble averaging the color. I remember this happening pretty often playing PS1 games. I could be wrong on this but it's what it reminds me of. Try and throw a decal or some vertex blending to break up the texture a bit and see what happens.

Xendance

It's called shadow map acne. It's not a flaw in the GPU drivers or anything, it's just something you have to deal with in all shadow mapping tech. The implementation in UDK is quite bad. You can tweak this by changing the shadow map bias in some of the config files, but too large bias results in peter panning shadows (ie detached shadows). I'd probably just decrease the radius of whole scene shadows if I were you.

JamesWild

praetus wrote: »

If I'm not mistaken this is a common problem when your texture is heavily repeating. The further away you get the texture has trouble averaging the color. I remember this happening pretty often playing PS1 games. I could be wrong on this but it's what it reminds me of. Try and throw a decal or some vertex blending to break up the texture a bit and see what happens.

That's "fixed" largely by mipmapping now.

Xendance wrote: »

It's called shadow map acne. It's not a flaw in the GPU drivers or anything, it's just something you have to deal with in all shadow mapping tech. The implementation in UDK is quite bad. You can tweak this by changing the shadow map bias in some of the config files, but too large bias results in peter panning shadows (ie detached shadows). I'd probably just decrease the radius of whole scene shadows if I were you.

I've had it show up in games it did not previously appear in after updating drivers, then disappear again after. When I was doing OpenGL dev some GPUs seemed to lie about the accuracy of their depth buffers. I don't think it should be a problem any more but it used to be one.

Yuke

I'm currently at work but I left my machine to build a couple of different versions of the Env going by some of the things here.. I also noticed its made more obvious when the normal maps are applied (but removing them doesn't get rid of the issue).. I'll post some screenshots in about an hour when I'm home!

Thanks for everyone's help This is something I've noticed a lot recently when I've been adding buildings into UDK, even after downloading the new version or opening new maps with default values.. It doesn't seem like this is a common problem though, which is odd! And I'm not sure what to search for in terms of finding a solution!

Yuke

Seemed to have partially solved the problem if the normal maps are disabled, however with normal maps on there is just a tonne of noise!

Diffuse Only:


Diff + Normal:

Yuke

Well I think I've found the problem.. and I think it's just simply the brick texture.. not really sure how to get round it!

If I change the texture to something that isn't repeating so heavily, like a tiling concrete texture rather than tiling bricks then the issue goes away.. If I increase the size of the bricks by a fair amount it also seems to solve the issue!

Here's a pic to show:



Adding a lot of extra objects onto the wall to break up the pattern slightly covers it up, but even small bare areas still have the weird shadow/texture problem

Froyok

The noise can also come from the texture filter : in you driver/ini settings are you using anisotropy of at least trilinear filters ?

Yuke

I can't seem to find the correct .ini file for that, should it be in my NVIDIA folder?

My UDK .ini file is set to "MaxAnisotropy=4"

sprunghunt

you could also try putting some fog into your scene so that things fade to a solid colour in the background.

HAWK12HT

i encounter similar issue (not exact).
Reading on this forum for almost a year i have found 3 major areas where beginers mess up when working with UDK.

1. UV mapping
2.Lighting
3.Modelling/Smooth groups


UV mapping :

IF you are using small UV shells overlaid on top of each other make sure they are not inverted, as normal map info gets confused for no reason even though your normals are flipped green. (note this is my finding on Feb build 2012) Its strange though cause inverted or not it dosent matter on texture UV. Your lightmap UVs should not be inverted.

Lighting

set whole scene radius to 3500 and settings below it to 3 and 4 or 10 10, in dominant light settings.
Make sure lightmap UVs are correct.
add light from top down and angle it about 10 15 degrees, Just a test , cause extreme angles like parallel to objects cause shadow acne and Z fighting stuff .

HAWK12HT

one last thing, UDK dont like plain simple clean textures, unless you are playing with ini settings and increasing world properties for high end arch visualisations.

Bottom line dirty up your textures and play with vertex painting.

JamesWild

If the problem only appears when normal maps are thrown on, is it possible that for some reason on your system mipmapping of normal map specific formats is broken? Experiment time:

Take one of your textures, and re-import it as a default compression type. Then in the material plug the normal map into a lerp between two 3-constants, 1,1,1 and -1,-1,-1 and plug that into the normal map slot. This'll unpack that default compression type into the range UDK expects. If it's no longer having the issue you know it's a GPU/driver issue with that texture format. Again, I've seen this happen before, but with grayscale images on some ATi cards, which were unfiltered and quite a performance hit.

Yuke

Thanks for the help guys, I'm away till Friday and don't have access to my work but I'm gonna try the things above.. I've got a feeling that my normal map settings are broken in some way, as even with some really clean normals they come out blobby when thrown into UDK and don't display the same results as they do in programs such as nDo2 or Marmoset.

Cheers for the help

McGreed

If that's the case, just remember to make sure that you import your normal maps with the right compression used for Normal maps, and not the ones you use for others like Diffuse.

Yuke

I've always imported with the correct compression settings, they're just appearing blobby and noisy on the bricks which isn't something I've encountered before