Texture problem

[nekrophiliak]

Does anybody know what's causing these pixellated edges on my textures? The normal and specular maps look fine when imported, I thought it might be a compression setting, or a light setting. Any help would be appreciated.

[screenshot]http://bulletholestudios.com/cho/art/problem.jpg[/screenshot]

[zephyr6831]

i'm not sure about this, but how big is the texture you're using?
and what image format are you using?
and how many ppi/dpi resolutions are your textures set to?

cuz if you're using a fairly small texture size, i it's blowing up the pixels bigger than they're supposed to be.
if you're using a lossy file format, that could possibly be the problem as well.
and if you've got a low resolution (ppi/dpi) that could also be a problem... the more pixels per inch there are, the smaller the pixels are in the image.

[nekrophiliak]

Yeah everything is 2048 X 2048, imported from targa files created using crazybump. I was using 1024 X 1024 so I recreated the textures and saw absolutely no improvement using the larger size. They're all 72 dpi, is this too small? I don't think it's a problem with the textures themselves, it seems to be doing it during the import process. I tried different compression settings, but nothing seems to produce a decent quality texture.

[DGUnreal]

Do you mean the pixelation on the rounded corners?

There is probably one of four issues going on (or a combination of):
- DXT compression is a lossy box compression, so you are possibly seeing artifacting.
- If you don't have the latest UT3 patch installed then you are seeing texture streaming issues.
- If this is a standard World LOD group texture, they do not support 2048x2048 (I have posted this countless times on these forums) so it will be dropping one or more mips.
- If you are using a pile of 2048x2048 textures on your map, you may be running out of pool memory and dropping down multiple mips on your textures.

DPI (PPI) is meaningless for game textures. That is for relating images to printing. Screen resolution is always in pixels. In other words, a 1024x1024 72dpi texture is identical to a 1024x1024 96dpi texture. Only if you print it on your printer will there be any difference.

Randomly trying different import compression settings should not be done. I recommend learning what they are before just "trying" them.

[Setheran]

So standard custom meshes should use 1024x1024 textures. But why do a lot of Epic's meshes use textures at 2048x2048 (in the World LoD group too, I'm pretty sure) if that size isn't supported?

[DGUnreal]

Unreal Engine 3 supports textures up to 8192. The actual maximum supported LOD/mip size that is displayed in-game varies depending on the LOD Group. For World it is 1024, for Skybox it is 2048, for Lightmaps it is 4096, etc. WorldNormalMaps also normally mip in at 512.

They would have designed a number of their meshes earlier in UE3's development cycle and used 2048 textures. Then most likely to get support on lower end PCs and consoles they bumped the maximum resolution down for the World LOD group to 1024.
On the few stock World Materials that use 2048 textures, you will only see the 1024 mip version of it in-game.

[nekrophiliak]

The problem is without trying the compression settings, you can't really tell what the actual compression is. Their labels (TC_World....) don't really let you know it will be using DTX1 or DTX5 until after the fact. Is there a way to better control the compression on normal maps? If I use a DTX exporter in photoshop will it recompress it on import anyway? How would you go about importing a texture to avoid these artifacts? I tried checking "Defer Compression" and it did exactly that, everything was fine until I saved the map and only then did it compress the texture anyway.

[DGUnreal]

The problem is without trying the compression settings, you can't really tell what the actual compression is. Their labels (TC_World....) don't really let you know it will be using DTX1 or DTX5 until after the fact.

It is all documented on the UDN.

Importing Texture Tutorial

Texture Properties


Whether it is DXT1 or DXT5 is specified with the CompressionNoAlpha option checkbox.
No Alpha = DXT1, with Alpha = DXT5.
This is used in conjunction with TC_ compression to determine whether any Alpha Channel data that is present in the texture is discarded or not.


TC_ compression specifies the compression style (there is no TC_World).
TC_Default is for regular textures (DXT1 and DXT5).
TC_NormalMap is for NormalMaps (they require special compression to retain the vector data).
The other TC_ compression settings are special case and are only used for specific items.


The LODGroup determines "where" the texture is going to be used in the engine.

TEXTUREGROUP_World is standard world geometry (CSG Surfaces, StaticMeshes, Terrain).
TEXTUREGROUP_WorldNormalMap is NormalMaps on standard world geometry.
TEXTUREGROUP_WorldSpecular is Specular Maps on standard world geometry.

TEXTUREGROUP_Character*** is for player models.

TEXTUREGROUP_Weapon*** is for weapon models.

TEXTUREGROUP_Vehicle*** is for vehicle models.

TEXTUREGROUP_Effects is for effects.

TEXTUREGROUP_Skybox is for sky spherical textures.

TEXTUREGROUP_UI is for interface (menu) textures.

TEXTUREGROUP_LightAndShadowMaps is for (you guessed it) lightmaps and shadowmaps.

TEXTUREGROUP_RenderTarget is for render targets.

Is there a way to better control the compression on normal maps?

The only options for NormalMaps are TC_NormalMap and TC_NormalMapAlpha. The common one is TC_NormalMap where the vector data is stored in the RGB as XYZ. TC_NormalMapAlpha is for textures where the NormalMap data is in the alpha channel, which is less common.

If I use a DTX exporter in photoshop will it recompress it on import anyway?

This version of the engine doesn't support import of DXT .dds textures.

How would you go about importing a texture to avoid these artifacts?

You can't. That is how DXT compression works. It is a lossy box palette compression system in order to reduce texture data size requirements. Sort of like "JPEG for 3D". It is the standard texture format for DirectX. So everyone uses it for game engines on DX/Windows systems.

There are specific styles of textures that show artifacting worse than others, due to the way that the compression system works. So you have to avoid some styles of textures.

This UDN page shows some comparisons and styles of poor texture compression. This page is a bit dated though so disregard its comments about DXT1 issues, that was for older NVidia cards that had issues.

I tried checking "Defer Compression" and it did exactly that, everything was fine until I saved the map and only then did it compress the texture anyway.

"Defer" means "do it later". In this case, it allows you to import the texture for use without waiting for the compression stage, which can be a few minutes on 2k/4k/8k textures. It later performs the compression when you save the package or map.

[nekrophiliak]

Thanks for the detailed response, I'll give it a try and let you know what settings work best for me.