Course Modding in Blender

[grandtour99]

How GT2's course files work (US Simulation disc, SCUS-94488 v1.0)

Everything lives in GT2.VOL (shocker lol):

• crsobj/*.tro: the track and everything beside it. Sections, faces, walls, which sections can see which, and where trackside objects sit.
• crsobj/*.trp: the course data the race loader reads alongside it.
• crsmap/: the 96x96 4-bit minimaps. Courses without one fall back to 2p_autumn's.
• crstim.arc: six images. 0 is the lamp flare, 3/4/5 are the car reflection maps (day, dusk, night).
• .crsinfo: one 24-byte record per course. Flags, the sky (an index into the sorted bgsobj names, not a file name), and three lighting rows that darken the cars per course.

Want to dig yourself? Load the disc in an emulator with a debugger and watch:

• Race set-up: 0x801D52BC. Event ID 0x801D52CC, course name 0x801D52DC, course key 0x801D52FC, race type 0x801D52C6.
• Current car 0x801D0FCC, credits 0x801D0FC8, days 0x801C9438, garage count 0x801CCFB4.
• Car models load at 0x8015F584, before the course. That's where the course memory ceiling (about 700 KB) comes from.
• Sponsor boards are drawn into VRAM at load, at x 640 to 704, y 0 to 256. The game picks them at random.

Find where a course file lands in RAM, set a read breakpoint, and follow the instructions that touch it. That's how every field gives itself up.

Here's Laguna Seca exported in Blender, which I can put back in the game when I'm done.

Happy to answer questions or just hear general feedback.

 

[CTRL Garage]

So you can replace and or upgrade tracks? Not add more to existing line up due to memory?

 

[grandtour99]

So you can replace and or upgrade tracks? Not add more to existing line up due to memory?

Yes. There are limitations, though. Like when you update meshes in the blender file, you have to ensure you choose the texture. Also, I've completed a port. So I'm working on the being able to add more, part. If you want to create a new track for the PS1 it has to be under 700KB.