I posted this a year or so back on OpenCarnage, felt it was useful to post here as well for posterity's sake.
I am by no way an expert on these, I barely understand them. I'll not be
this with more indepth info and how they're used for plasma shields as I look more into it, for now I needed to know this information was available SOMEWHERE.
3d or Volume textures can be thought of as a cube, cut into slices. Each slice will be different, but will blend with the ones before and after it, creating a neat cross-section like view that's best described by none other than Michael Meyers as shrek describing ogres as onions
These slices are arranged horizontally side by side.
To start, you need to take the texture "Characters\Elite\Bitmaps\Plasma Shield Noise" and extract it to a .dds with eschaton. Then open it with photoshop, and resize it so that the height is 128/256, and the length is in proportion.
Slice vertically at 128/256 pixels, making 32 separate squares. Edit these textures to make your bitmap. Now, once your finished, open a new document with photoshop, and get out a calculator.
Take each slice and make it into a separate document. Add a 1PX fully-blue border to each image, then copy and paste them all horizontally into a single bitmap. If done correctly, the total image size of the new bitmap should be;
[bitmap Size (128,256, etc.)] * [Number of Slices (32 Stock)] + 64
If it's not, you did the borders wrong. 1 pixel on all four sides of each slice. So inbetween slices is 2 pixels, one from each side.
Compile this with tool, then change the settings to 3d Texture and 32bit Bitmap in Guerilla. Then recompile.
When you do the above you can change the bitmaps they use for the energy shields, or find new uses as well!