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Early attempts at exporting huge 3DO's to 3D Studio Max. Recognize the grass of Zandvoort? Guess not. ;-)

WHAT YOU NEED

Before diving into GPL track conversions, I'd advise getting the game. At the least when you are converting existing tracks, but also when converting new tracks that were made by different people. GPL was and is still a great inspiration, and playing it will tell you why (with the dangerous side-effect that you might get hooked on it and stop playing Racer for a while though).

So to convert from GPL to Racer you then need little, except:

• Grand Prix Legends from Papyrus.
• GPLex (available at this site, pronounce G-Plex).
• WinMip, to convert GPL's rather ancient MIP/bitmap format to BMP.
• Home-made GPL tracks.

Recommended also is:

• 3D Studio Max or some modeler which imports WRL (although Racer's Modeler might be able to load the WRL files).
• A bit of disk space (though Zandvoort was just about 5 Mb).

GENERAL CONVERSION INFORMATION

Importing GPL tracks is not as simple as importing SCGT tracks. GPL uses the 3DO format, which is a mix between all kinds of trees. Looks like it's a BSP tree for rendering, but I think it also contains bounding boxes for collision detection.

So the trick was first to understand a bit about the tree format. The indispensable site for inside information about 3DO's (and other GPL file formats) was at Phil Flack's site (I can no longer find that on the internet though). You can skip that though and move on to using existing applications.

Next the problem is that rendering trees are not flat linear objects, like SCGT and Racer uses. So the idea is to break down the tree and create a separate object for each texture that is used. In short, this is the flow of work when converting a GPL track:

• Extract the track .3DO from the .DAT file.
• Convert it (using GPLex) into texture-separated VRML files (.WRL).
• Convert the textures to .BMP (or .TGA) file format. BMP is what is generated in the .WRL files from GPLex.
• Optionally optimize the .WRL files in any modeling package, such as Max. This is mainly to get a better topological layout of the polygons (meaning that polygons that are close to eachother in the world are also close to eachother in memory; this improves rendering performance later on).
• Convert the lot into .DOF files (you can use TrackEd's batch WRL import; place the WRL files in <trackdir>/SCGT/wrl).
• Break up the track into smaller files. Easier said than done. You may do this in Max for example. Ofcourse, plans exist to do this automatically later on, in Modeler probably. Keeping the huge models is a good way to bring down your framerate (that was sarcastic).
• Proceed as usual to create a Racer track; see the TrackEd page, importing SCGT tracks and Creating a new Track. Add a track.ini file, a track camera (or rather a couple), add grip/pit positions and at least 2 timelines. This all to get the track accepted in Racer.

Perhaps even better is to now switch to the GPLex documentation, which is more up to date. You can also read on. :)

THE STEPS IN ENGLISH

First, get the .3DO out of the .DAT file. For GPL regulars, this is not too much of a problem, and I may describe this later.

The other steps may also feel familiar. I must elaborate on those later. Try the forum or any of the GPL forums for more help for now.

TEXTURING

Previous attempts using Paul Hoad's GPL Editor seemed the need to cut out all LODs except the one you want. GPLex only exports the highest (most detailed) LOD of the track. Also, texture coordinates are exported as well. Let's not waste time on that!

Notice in the image on the right how the texture flows along with the imported model. This is the 'Grass' texture from Zandvoort's ZANDVORT.3DO in 3D Studio Max R3. Note that later GPLex versions do a much better job (almost perfect) of converting the GPL track data to regular (more linear) 3D models.

(last updated November 13, 2012 )