A resource for Geoff Crammond's Grand Prix 4

Installing new cars is perhaps the first thing any modder will try when modding the game for the first time. However, it's not the simplest topic to understand. This article explains the basics of installing new cars and how to troubleshoot some common mistakes.

IMPORTANT! Non-CSM version. This tutorial is about installing cars without using CSM. If you are using CSM please refer to the CSM tutorial instead (which hasn't been written yet...)

The 22 cars are stored in a file called cars.wad, which is in the main GP4 directory. To open this file, you must use a program called Easywad. Easywad is part of the ZaZ Tools package.

Each car requires 5 shape files (.gp4) and some texture files (.tex).

Shape files (.gp4)

There are 5 shape files per car. The filenames of the shape files must follow a set pattern, as follows:

car_[teamname]_car[1 or 2]_lod_[0-4].gp4

There are 11 teamnames, and each team has a "car1" and "car2", giving us 22 cars in total. For example:

car_ferrari_car1_lod_0.gp4 -> Most detailed shape, used when the car is closest to the camera
car_ferrari_car1_lod_1.gp4
car_ferrari_car1_lod_2.gp4
car_ferrari_car1_lod_3.gp4
car_ferrari_car1_lod_4.gp4 -> Least detailed shape, used when the car is furthest from the camera

The 11 teamnames (sometimes called slots) of 2001 are hardcoded into the game. They are, in order: ferrari, mclaren, williams, benetton, bar, jordan, arrows, sauber, jaguar, minardi, prost. Cars must use one of these 11 teamnames.

REMEMBER! You cannot have more than 22 cars in GP4, because that is how many there were in 2001. You can have less than 22 cars by disabling cars using GP4 Tweaker (numcars.ini).

Texture files (.tex)

Each car requires at least one texture file. The amount of textures depends on the author of the car, but usually there are between 2 and 5 textures per car. The original GP4 cars all have 3 textures.

For each texture, there are 2 copies of the file, a high-res version and a standard-res version. The high-res version adds the prefix "hi_" to the name of the texture file. E.g.:

ferrari_1.tex [see example]
ferrari_2.tex
ferrari_3.tex

hi_ferrari_1.tex [see example]
hi_ferrari_2.tex
hi_ferrari_3.tex

GP4 will load the standard-res car textures if the Car Textures option in the game Graphics menu is set to medium (this is the game's default setting) or low / 16-bit. The high-res car textures are loaded if the option is set to high.

Screenshot of Graphics Menu here >>.

IMPORTANT! Do not rename texture files. The car shape files (.gp4) contain pointers to the texture filenames. If you rename the texture files, the pointers become invalid and so the car will appear white because the textures cannot be found.