steve-m.com » CollEditor 2 » FAQ

What is this?

Collision File Editor II is a program for creating and editing collision files used in the games Grand Theft Auto III, GTA: Vice City and GTA: San Andreas.

So I can model my own collision models?

No. This program is mainly for editing them, with focus on the special face properties (like materials and lighting). You still need a proper 3D modeling program like 3D Studio Max or ZModeler.

Which files does it import?

The current version only imports Collision Scripts (*.cst) and 3DS models (*.3ds). More file formats are planned.

What the hell are Collision Scripts?

Collision Scripts (*.cst) are a text file format I invented for CollEditor back then, and which is now available in a new, more flexible version. This format was mainly created to provide an easy way to create own collision model descriptions by hand, and to be able to easily export from programs that can't write binary files (such as the old 3DSMax 3.1).

There is currently no script to export to the new format from 3DSMax, you would have to use my old export script.

Sample files demonstrating the file format can be found in the CE2 download package.

What are the differences between the 3 col file formats?

For a detailed description of the collision file format, see this article.

What are face groups?

Faces in large col 2/3 meshes (more than 80 faces) are grouped by location, and get a bounding box. This way collision checks can be limited to a special area of interest, to speed them up significantly.

What is face brightness?

Brightness (or light intensity) is a new feature of the col 2/3 format. They are a simple but effective way around realtime lighting. You can define a 1 byte lighting value per face, which causes characters and vehicles to change their brightness. This is used to simulate shadows and dark areas.

What is a shadow mesh?

The so-called "shadow mesh" introduced with version 3 is used to cast real-time shadows in GTA SA (PC). To save cpu time these are reduced to significant parts of the object, like bridges on map parts. Spheres or boxes are not available here.

My shadows look messed up, why?

That's probably because your shadow mesh isn't closed. If that's the case, a bug/limit in SA causes odd projection errors, with shadow triangles floating around. So always make sure your shadow mesh doesn't have any holes.

Are there any limits?

In GTA III and VC collision meshes are limited to a few thousand polys. In GTA SA however, no such limit is known. But that doesn't mean your mesh should have thousands of poly, that defeats the purpose of the streaming engine. Better split your models up into several small objects.

Also, due to the compression used in the col 2/3 format(s), vertex positions are limited to +/- 255.99 units on each axis. CE2 takes care of that and warns you on exporting.

Can I mix models of different versions within one col file?

Yes, that's possible. Just make sure the target game's engine supports all those formats. (E.g. you can't use COL3 in VC.)

What col version shall I use?

For GTA III and VC you have to use version 1. But for SA you should always use COL3. If your model doesn't have a shadow mesh, you could also use COL2 to save 12 byte.