Extensions used for Diffuse texture maps

kevingamerartist

Hi all,
I've got a quick question about Diffuse texture maps. I have been using JPEG images for my Diffuse textures, and the program I'm using for 3D Modeling is Maya. Is JPEG a good/decent image format to use for Diffuse textures, or should I be using a different file format? I'm not sure if I should be using a different file format since I'm using Maya, or if it doesn't matter.

Any feedback or advice on this is greatly appreciated. Thank you

Eric Chadwick

JPG is a lossy format, which means every time you save, it adds more noise. Not a good idea for texturing.

Better to use a lossless format, like PSD (if you're using Photoshop) or TGA or TIF. Re-saving these formats will never add noise, because they are lossless.

JPG doesn't have an alpha channel, which is often needed for various game materials.

If you're creating models for a web-based game, then JPG might be recommended since it downloads fast. But this is rarely used.

We have some stuff here
http://wiki.polycount.com/wiki/Texture_formats

kevingamerartist

For TGA files, they are only 8 bit correct? Sorry if this sounds like a silly question, I just want to ensure that there isn't a 16 bit TGA file or anything that I should be using instead, or if 8 bit is the only format for a TGA file.

RN

According to the Wikipedia article, 32 bits per pixel is the highest option available for TGA.
In this case it's using true-colour 24 bit RGB data and an 8 bit alpha channel.

Note that it's your game engine that dictates what formats you can use, then you can pick the one that supports the features you need and is the most convenient to work with. You should consult the documentation of your game engine to know the preferred texture asset format. Unity and Unreal support PNG, TGA, TIFF etc. CryEngine only supports TIFF files, for example, and only through Photoshop.

I think there was a discussion in this forum on PNG vs. TGA and that some artists prefer using TGA files because Photoshop has better tools or worflow for them (the exporter is stable, you can define an explicit greyscale alpha channel etc.).

Eric Chadwick

Yep. TGAs can be 8bpp (256 colors), 16bpp (65536 colors), 24bpp (16m colors), or 32bpp (24bpp plus alpha).

TIFF supports all those, plus it also supports higher bits per CHANNEL (bpc). There's 8 bits per pixel (256 colors) and there's 8 bits per channel (16 million), two very different things. The options for saving or converting a texture don't always tell you which one it is, but usually they mean bits per pixel.

Normal maps for example are best to make at 16 bpc or higher, so you can edit them without color-banding artifacts. HDR also requires higher than 8 bpc.