art-true-3d v2-27-2002 Release 4 © RTCM W0rm
As we all know, duke doesn't use "true 3d". If you define true 3d, it is simply the use of polygons or voxels to get a 3D look. We are still however, simply looking at a flat monitor, so no one can really say that it's 3D, it's all in appearance. Right now, the closest looking thing to 3D is polygons, so we call it "true 3d", possibly when a newer technology comes out, it will then become "true 3d".
Duke has its limitations, we cannot modify it to use polygons and Kens Silverman's voxel engine wasn't added to v1.5(it wasn't ready), so why can't we use the next best thing, Simulated voxels or polygons. Considering 3D is only appearance, we can make duke3d appear to be 3D. You may need some knowledge of the CON files.
-5 sided (4 unique view angles, 8 sided, 3 mirrored)
action PSTAND 0 1 5 1 1 // This is the action for duke standing still.
Notice the 3rd number, 5, that means that this action will be using 5 images to make it appear as though duke has 5 unique sides to it. The action will actually treat every 5 images in that area of the art tile as one image. The game automatically mirrors or flips the sprites to complete a 360 degree view angle when using only 5 images.. The top and bottom views don't exist, they are 'faked' by warping the perspective angle. Meaning you will never be able to see the top of duke, but only a stretched side view.
-1 sided (8 view angles, 360 degree rotation )
You'll notice in the game some actions only have one side. Those actions use the same tile to display the sprite for all sides of the object, and for all angles you view an actor during the game.
-8 sided (8 unique view angles, 8 unique sides)
I searched the entire GAME.CON file and I didn't see a single action using 8 tiles/textures. Possibly because the game automatically flips the image to be viewed from a different angle. However this limits the detail available or capable by the game. Using 8 sides and making the textures each unique will tremendously improve visual quality of the game. It may add a slight performance drop, but its worth it.
-More than 8 sides (
I'm not sure if the game accepts values over 8. The chances, however, are quite slim that it actually functions higher than 8. Since duke seems to be based on providing one image in increments of 45 degrees. The game may actually take higher values but ignore them, effectively defaulting back to 8.
I have tested values up to 25 and they all seem to compile with no errors when running the code. Though I do not have the art to test them correctly. With this possibility, you may be able to use higher values to create an extremely real looking environment with duke!
By adding more tiles/textures into the art files, along with changing the action to 8
or 5 depending on which would be necessary to get the effect and how much detail you want,
duke could look entirely 3D. Almost everything in duke could be made to look as though it
was using voxels or polygons. (Note: Some later BUILD games have a working voxel