Gran Turismo 1 car model specs

thegreyman1

This probably isn't the right forum to ask but here goes. Does anybody know what the specs were for the car models and textures for the first, and even second (if it was different) Gran Turismo game on PS1?

I love the "style", if you can call it that and I want to make something similar so I'm just wondering if anybody knows the solid triangle count/texture sizes they used per car. Its been extremely hard for me to find any info on this as I imagine Polyphony digital wouldn't exactly be all that open to revealing their methods.

Xoliul

Just going by screenshots, I imagine each car is about 500 tris max, perhaps less. Texture sizes for the body are probably 256x256. Wheels might be on a separate sheet, looks about 64x64.

Sound like fun specs to work with, you'd be able to do a car in a day or two i think

thegreyman1

Exactly Thanks Laurens, when I make something I'll post it up. And thanks for all the shader work over the years BTW, I got many a job because of how cool you made my work look :thumbup:

SonicBlue

Xoliul got it right, for example in GT2, the [R]Stratos has 412 faces, while the RX-7 Type RB only 280, all without the wheels, which I think are stored separately probably associated with the alloy wheel texture they represent. The the car body texture is 256x224, it includes the LODs too.

If you want to take a direct look at them:

http://z3.invisionfree.com/Our_ReVolt_Pub/index.php?showtopic=1835

JordanN

Since this is about Gran Turismo, there's something I've been meaning to ask.

How did they fake those reflections of the sun and sky on the playstation 1? Could the PS1 handle environment or cube maps? And what about the shadows? Are they just Shadow Volume or a texture that follows the car?

Swizzle

The PS1 was certainly able to handle cubemaps, though I couldn't say what texture sizes. If you play GT1 or watch videos, the trophies you get have cubemaps rendered on them, and the cars all have some sort of reflections.

As for the shadows, I think it's just a plane that sticks to the ground under the car. I don't think the PS1 was capable of rendering any sort of realtime shadows, so the best solution was probably a simple polygon plane with either a very small texture, or vertex colors.

Snader

Yeah those shadows are definitely a simple octagon. And I wouldn't be surprised if the reflection texture was a single screenspace one instead of a cubemap.

But if you're just emulating the style, yeah stick to about 500 tris and a 256² with a simple cubemap in engine.

Leo2236

thegreyman1 wrote: »

Does anybody know what the specs were for the car models and textures?

In GT and specifically in CARCADE.DAT cars main body have 136~244 polygons(triangles + quads) not counting LOD models(theres two more LOD models in car beside of the main model) I also don't counting bottom of the car as it use different type of face and the wheels(they are stored elsewhere anyway), theres also shadow model which I don't counting neither. As about texture GT use 256x256 4bit each car color can use 16 palette max.

Anyway here and some time I'm trying to create a tool that could view and maybe in the future export(to some common format like *.OBJ) cars from GT and this is what I have right now Pic1, the tool already can view all the cars but only those from CARCADE.DAT there's still some bugs to fix and features to add before I could release it but once I'll do that(hope soon) I'll post tool here so everyone who is interesting could download it.

Pic1: GT Car Viewer v0.1b


Hello SonicBlue nice to see you! You are the same SonicBlue from the RE123 community aren't you?

Leo2236

GT Car Viewer v0.1b:


Note: Do not use www.datafilehost.com downloader it's problematic I've heard, so before downloading uncheck the related checkbox.

GT Car Viewer v0.1b.EXE (623.09 KB)