Home

A John Player Special Lotus from 1970 in one of the oldest versions of Racer.

Introduction to car creation

Racer is designed to allow you to create new cars relatively easy (especially compared to racing simulations such as rFactor). Cars are stored in the installation's data/cars directory, under their own directory (i.e. 'data/cars/porsche911'). Don't use spaces in the car directory (actually Racer will automatically detect and rename such directories!). Also it is advisable to use lowercase characters only to provide easier compatibility with non-Windows operating systems such as Linux (Mac OS X is actually case-independent).

A car's physical and graphical appearance is mostly defined through its car.ini file, which is stored in the car directory (data/cars/porsche911/car.ini for example). This file contains the physical details, such as suspension settings, CG (center of gravity) location, graphics models, tire parameters etc. For a reference to all car variables (in the car.ini file in data/cars/<yourcar>), go here.

Starting out

Before jumping in, it is wise to at read the general instructions on (content) development for Racer. That article describes tools that will help you troubleshooting the problems that come up during the creation of a new car. After knowing what's available to you as a car and/or track developer, come back here.

There are a LOT of details available to you when you start a new car. Therefore, it is advisable to start out with a car that looks and/or feels similarly to the car that you want to create. This avoids having to start all the way from scratch. To make the basis for your new car:

• Copy the existing car's directory.
• Rename the directory copy to match your car's name.
• Edit the car.ini and at least modify the car's name (car.name).

Areas of expertise - graphics and physics

There are 2 things when it comes to creating a new car; 3D models and physics. Most people will find either of these 2 the most interesting. 'Tuners' (people who are more inclined to tweak the physics) can be contacted at the forum. Perhaps it is even best to split this job apart in these 2 disciplines.

Which car to model

Lots of cars are already available, but Racer seems a bit like Lego; many people want to create their own models. It's part of the fun of Racer. For inspiration, visit Sports Cars.org for some nice cars you might to model.

Graphics - obtaining car specifications

A lot of information on a lot of cars is available on the web. You may check the links page for a lot of Internet links. Also some relevants sites are listed here:

• Blueprints - visit Suurland for lots of car blueprints.
• Tutorials 3D Blueprints - a site with 3D tutorial (for money) but with lots of free blueprints.
• Car images in various angles; excellent image site is NetCarShow (loads of car models in all shapes & sizes and good photos to base your models on).
• Check Carfolio for important numbers (track width, max. torque etc.)

For Grand Prix Legends F1 (1967) cars, there is a lot of technical info at these places:

• Eagle Woman
• Richard Nunnini

The car's reference point - the nullpoint

Cars have a design reference point, which is called the 'nullpoint'. It normally is nearly the same as where you'd put the CG. But as the CG may be tweaked a bit (fuel changes for example, or driver movements), you need a static reference point from which all other points in the car are defined.

For more information on the nullpoint, see the tutorial about the nullpoint.

Creating the 3D models

To create the models, you'll need a modeler. I recommend 3D Studio Max and export using .ASE files. The ASE importer is one of the most used formats for me personally (so it also probably does best at importing all of the available data). Other than Max, you can also use Maya or SoftImage or whatever you feel like. If you want to use a free modeler I'd recommend ZModeler or Blender, which has a DOF import/export filter so you can work very directly.

ZModeler tutorials:

• Modeling a Saab on GRIDsite.
• Creating a car from scratch at Awesysnet.
• More car creation tutorials (and other tutorials on Racer)
• Modeling a Lotus

More information on usable modelers can be found in the modeling tutorial.

Also note that v0.9 of Racer has a Cg and a non-Cg version. You can support older cards by providing a car_nocg.shd file, which is loaded when you run 'racer_nocg.exe' instead of racer.exe. More information on doing without Cg here. Information on Cg/GPU shading here.

Creating a collision shape

Check out the tutorial on car collisions for detailed information.

Things to know

• When modeling a new car, make sure you place the body model's center near the center of gravity of the car. This will make the rotation motions look better, as the car is rotated around its origin while driving (there's no explicit pivot point). In other words, if you rotate your model around the origin in your 3D modeling program, it should closely match the pivot point it would rotate around in real life (if that makes things clearer).
  This is really a bug that's been inside Racer for a long time.

Creating car cameras

See the tutorial on car cameras for more information.

The Steering Wheel

You can add a 3D model to your car by adding a 'model' section in the 'steer' section (in car.ini). A bit of hassle is to get the XYZ parameters right; just use your car cameras well to figure out a nice location for the steering wheel. If no model is specified, no steering wheel will be displayed.

Views (groups of dials)

Check out this page for all the information about creating sets of dials for the car.

Creating the physics

The physics of the car is an art in itself, just like setting up real cars. The best place to start is the car.ini reference guide, which contains explanations & tutorial links for all the available settings that make up a car (and it's a lot!).

Spicing the car up

Optionally, why not make your car even better:

• Add glowing brake discs
• Add level of detail for faster rendering
• Add suspension
• Add wings (aerodynamics)
• Add (projected) lights (front lights)
• Add a fuel tank

Debuggin the car

Racer helps the content creator to verify what the car is doing. Taking care of the following points helps:

• Read the development page, which explains generic ini files, the QLOG error/warning file and general development tips.
• show_car_points; in racer.ini, set gfx.show_car_points to 1 to see a number of useful reference points, such as the roll centers, the roll plane, suspension points and things like the Center of Gravity. See the image below for an example. Check the suspension page for the per-wheel points. You can also turn the carpoints on/off using the script commands 'show carpoints' and 'hide carpoints'.
  

Tips

• A lot of default car parameters are defined in data/cars/default/car.ini. Parameters undefined in your car.ini will be searched in the data/cars/default/car.ini file. This can be confusing; since v0.6.4 there is a dev.note_ini_fallback setting in racer.ini. Set it to 1 to get messages in your QLOG file on variables that are found in the default car.ini file, rather than being found in your file. Note that parameters that are found in neither the local nor default car.ini files are not written to QLOG.
• When you zip the car file for distribution, please include the desired directory name. This way you avoid getting all kinds of directory names in everybody's installation. Besides, it's easier like that.
• Use all lowercase characters; this is useful for Unix versions where case matters in filenames. Internally, Racer makes most filenames lowercase to make it easier for Unix versions to use content generated on Windows (or Mac, which are both case-insensitive). This goes for filenames, but is generally useful for things like shader names, entries in .ini files etc.
• The number of polygons; 10,000 polyhons for the whole car including wheel seems ok, but ofcourse is very dependent on your graphics card these days. GT3 on the PS2 seems to use about 5000 polygons/car, but probably uses more LOD models. Also make sure to use as few textures as possible; every texture switch is very costly; try keeping it in 1 1024x1024 texture for example (like CMR2 did for example).
• Textures; as above, the fewer, the better. Better is 1 1024x1024 texture than a few 256x256 ones. Max texture size I would say is currently around 2048x2048, although keeping it to 1024x1024 for now is recommended.
• Image file format; use .tga files instead of .bmp files. .TGA files should load faster, and all .bmp files are keyed on purple, which costs even more CPU time (especially when no purple is present, so it's effectively not used). JPEG files are possible, but are lossy so not recommended.

Links for physics info

For useful technical information about your new car, you may want to check out these links.

• Detailed information on Subaru cars (gear ratio's and a lot more)
• Suurland's excellent site for a lot of car blueprints
• Information on a lot of engine weights at PerformanceUnlimitied.

Releasing your car to the public

When you're ready to display your car to the public, take some notes on how to do the release. See the Release Document.

First and foremost is to run your car and then check QLOG.txt for errors & warnings. A lot of cars still generate many warnings which are unnecessary. There is a page on fixing common warnings.

(last updated November 13, 2012 )