Tank tracks for C2

Well this is a very interesting and annoying topic. Basically, its a right pain in the arse to set up... here's one way to do it. You may find it useful to download the accompanying Demo Car 3. It assumes you know how to use CarEd (or another modeller, and can set up your cars for C2), and PT2 for adjusting the mapping. It is also pretty advanced, you need to know a bit about Grooves and Funks.

Set up your car as you normally would... obviously this time add tracks.
For the tracks, set each one up with 4 parts: top, bottom, front, back. These can be grouped into left track and right track.
Make a track texture (you might find it handy to make a simple arrow for now, to make mapping the directions easier). In CarEd, set up 4 new materials, naming them tracktop, trackbottom, or similar. Browse to your track texture for all 4 materials. Assign these materials to the relevant parts: tracktop to your left and right tracktop parts, etc. Don't worry if they don't all point the right way, this will be changed in PT2 later.
Compile the car. Everything should be fine, and the car should run in C2 (better test it now, just in case).
Now, load up your car's text file. You need to remove the steerable flag from the front wheels. Firstly, change the number of steerable wheels to 0, deleting the 2 lines that come after it in the process:

0                   // Number of steerable wheels

Then remove the FLPIVOT and FRPIVOT parts from the Grooves section (if this confuses you, check the text file in Demo Car 3, makes sure your Groove section matches that one). Also, change FRWHEEL and FLWHEEL to match the format of RLWHEEL. Be sure to keep unique GroovyFunkRefs (if this confuses you, check here for an explanation).
Make sure your GroovyFunkRefs (GFR for short now) match up with the ones listed in the driven/non-driven wheels (for spinning) section. Save the text file, and test the car... it should still be moving! The front wheels should not turn, but the car should.
If all is ok, you can proceed to setting up the moving textures for the tank tracks. This goes in the Funks section. Don't forget "NEXT FUNK". Here is the code:

trackfront	// name of the material, as we set up earlier
constant
roll
controlled
-1,9		// these 2 numbers are explained below
no fucking lighting
no animation you cunt

Good eh? Ok, so you need 4 new funks, one for each material we set up earlier. The numbers are the interesting part. "-1" is a placeholder, meaning it does nothing. The other number is the unique GFR that you assign to this part (it must be one that no other part uses, hence unique). Now, those are the two numbers you need. If you want your tracks to go forwards/backwards (which you do) then you will use the "-1,(GFR)" configuration. If for some weird reason you want them to go left/right, you can use "(GFR),-1".
"controlled" means that they will move only when the car does. For the game to know when to move the tracks, you must put the GFR of each funk into the driven wheels section. Just replace the -1's. If there are already GFRs there (from the wheels) move these to the non-driven section, they don't need to be driven anyway.
Save and test. You should find that all your textures move the same way around the tracks when the car moves. However some of them might be going backwards, that is ok. This can only be fixed in PT2! Don't try with CarEd!
Open your car in PT2, and fix any textures which don't follow the forward direction. To do this, use the pick tool with faces selected, and click each polygon for that part (e.g. trackfront) until the entire part is highlighted in green. Then load up the manual mapping tool (F5) and press the 'flip vertically' button.
If your tracks were going backwards, you now need to 'flip vertically' each track part as described above, so that the arrows all point the way the track would rotate backwards. There is a quicker way to do this too, you can select the object e.g. LTRACK.DAT, and then under the Materials menu, click 'Flip textures in vertical' (I am using the improved PT2 by Cesm, you may need to get that if the original does not have this function. Or you can do all parts as described above).
Save as carname.sdf, then update the relevant model files (dat, act, mat etc) in your C2 directory. Test the car, you should find that the textures all move the correct way now. You can correct the arrow direction by rotating your texture 180 degrees in your paint program.

That's it, I think! Hopefully I didn't miss anything... in my Demo Car 3, I didn't bother with setting up suspension, so rather than have the wheels show through the track, I simply removed all the suspension GFRs from the text file (replacing with -1).