How to DDS Export

[Pherim]

Here is something I just realized and I wanted to share it with all texture artists:

 

Do not use GIMP for .dds export! It will result in bad mipmaps!

 

Most of the time this won't matter much, but especially for textures with alpha channel (transparency) this can become a problem. I first realized it when I played around with a self made grass texture in Oblivion, wondering why my own texture looked alright in close proximity but increasingly bad in the distance. Not only was did it have jagged edges, but it also became darker and more saturated, which made it stand out most unpleasantly instead of blending in with it. I had already noticed this problem with this Oblivion mod before but I couldn't pinpoint it's cause, blamed Oblivion's engine or possibly OBGE for it. But strangely enough, other grasses did not have this problem and that was when I thought that it might be caused by the mipmaps, which made sense given that it only appeared when the object was seen from a distance. I remembered that I had already made the observation that Gimp is quite bad when it comes to resizing images. And as mipmaps are nothing else but resized versions of the main texture, I tried exporting the grass texture with Paint.NET, which in my opinion has very good resizing quality and also built-in .dds export. And suddenly the grass looked so much better, all problems mentioned above were gone. Then I tried it with the texture from the groundcover mod with the same result. Here is a comparison gif: https://lh3.googleusercontent.com/-1yIiU8JcHbA/VRc7kG3r3WI/AAAAAAAACPQ/FEdYNsWQHaU/s0/mipmaps.gif

 

I am quite certain that the creator used Gimp for exporting the texture, as it looked exactly the same when I re-exported it with it again. The difference in the running game is even greater than in the comparison gif, and the further away the groundcover is, the worse it gets. It might depend on your screen and settings how apparent the difference is, but when it comes to the grass texture, it's immense. I might also provide a comparison of that tomorrow or so.

Now that I know of this, I will revise some of the textures from my own Morrowind mods (especially the comberry plant) and see what difference it makes in Morrowind. If there also is a noticeable improvement I will probably update them, but we'll see.

 

I hope this was helpful. I for one will not use Gimp for resizing and .dds export any more. However, it still is a great application, and I will continue using it for creating textures and other things. But from now on I will export the finished texture in a lossless format first and then create the .dds and mipmaps with Paint.NET.

 

Edit: As I was just reminded, the GIMP .dds plugin has a lot of options for mipmap creation, including the filter mode. There are many to choose from and probably some are better than the default one. Maybe I'll try them out and compare them to the default one. Still, I assume many people (including myself) don't think much about this and just use the default setting. So I believe it's important to make people aware of this.

Edited March 29, 2015 by Pherim

[Mudran]

I bump this, because I would like to know how is it too and because here are some informations, that are useful.

I have found this tutorial:

http://vandaengine.org/an-overview-to-common-compressed-texture-formats/

http://vandaengine.org/how-to-export-your-image-as-compressed-dds-file-in-gimp-with-gimp-dds-plugin/

And I have still this problem:

The vanilla textures of eyes and eyebrows don't have transparent background in the game texture sets, but a color, which I guess makes the texture lighter/darker in the game, but when I open it in Gimp, it is transparent only.

Does anybody know where I can get that color? (for Snow elf it is beige)