I've been looking in the forums for a good terrain modifying tutorials for making terrain changes or customer terrains. Please tell me your favorite. There are often many ways to approach the issue, and as a beginer, is tough to know which approach has worked for people.

yeah that would be kool.. to get some starting tips :D

1. Unpak the original Assets
http://forums.civfanatics.com/showthread.php?t=136023

2. Acquire the needed tools:
http://modiki.apolyton.net/index.php?title=How_To_Modify_DDS_Files

3. Modify the terrain textures in
Assets\Art\Terrain\textures

Most terrain consists of 128x128 tiles (see "noterrain.dds").
Hills and peaks consist of 255x256 tiles.

I have been doing some terrain modding and have some limited success. Some things I haven't quite figured out yet:

1. What is the purpose of the layered "mipmaps" in most of the terrains? Are they for different levels of zoomed views, or just an artifact of the way .dds stores data?

2. How are terrain textures used? I presume that the light-dark gradation has something to do with the texture "heights" of each terrain, but it's been hard to experiment with. I noticed that the ocean texture is completely flat/gray. Is this color gray the lowest elevation possible (assuming my theory of texture contouring is correct)?

3. Has anyone figured out how, exactly, the water textures work? After some significant SNAFUs, I found that the graphics engine just takes (one, some, all?) of the water images and slides them left-to-right or right-to-left. As they intersect, some algorithm determines whether the result is transparent, opaque, or in-between. How that operates, exactly, I don't know, nor do I know what "magic" is involved with the original graphics to make it look like moving water.

btw I've been using GIMP to change from .dds to .png and then using Fireworks (the only decent graphics program I have) to mod the images.

Update and answers to my own questions:

1. Using GIMP I have been unable to create mipmaps as I believe they were intended (which, I think, is to allow the software to select the appropriate size graphic for a given zoom level and thereby save on-the-fly re-sizing computational power). Instead, all I could do was create blank mipmaps, which would cause terrain to show up magenta unless zoomed in totally (and centered). Therefore, I found that using a single layer is best unless your graphics program has the ability to generate different-sized mipmaps, which I can't seem to get GIMP to do. (If anyone has any suggestions please post them!).

2. Terrain textures seem to operate like textures in graphics programs -- they are overlaid on the terrain and mask them. They don't have anything to do with 3D texturing -- that, I presume, is in the mysterious NIF file.

3. There is an XML file that selects the water terrain and also manipulates it. Exactly how I'm not sure yet, but I plan on playing with the various values (which, I believe, include rate of scrolling and what happens when colors collide).

About your problems:

1. DDS files have to be a "power of 2" size in order to generate the mini-maps. Was that your problem?

2. The NIF files are the 3d models, they have nothing to do with the textures on them. The DDS files are the skins that are put over the models.

Rabbit_Alex:

1. No, the problem seems to be with GIMP, or the way I configured GIMP, or something like that. The terrain files are all 512x512 or 256x256.

Thanks for your reply!

Are you using GIMP to save the images as DDS files? There is a plugin that lets you do that. Or were you using a seperate converter program?