Welcome to the Arena, where high-ranking warriors are transformed into spineless mush. Abandoning every ounce of common sense and any trace of doubt, you lunge onto a stage of harrowing landscapes and veiled abysses. Your new environment rejects you with lava pits and atmospheric hazards as legions of foes surround you, testing the gut reaction that brought you here in the first place. Your new mantra: Fight or be finished.

Report article RSS Feed BSP-Level based game Engines

This tutorial explains how the technology behind the mapping process works, and how the game engine knows what it has to calculate. The required background knowledge is included.

Posted by Chrissstrahl on Nov 27th, 2009 Page 1 of 10    
Basic Mapping/Technical.

BSP-Level based game Engines

(mainly the id Tech 3 engine)

  1. The author can not grantee that the information provided in this tutorial is perfectly correct!
  2. The author assumes that the information in this tutorial is correct and the tutorial is written in a casual and non over-tech-termed manner.
  3. This tutorial does NOT teach you how to get started with mapping or how to modify a BSP!
  4. This tutorial is based on id Tech 3 engine with Ritual's ÜberTools 1.1, some technical specifications can be slightly different from the stock id Tech 3 engine.


A level which will be Compiled into a BSP is build with many different kinds of objects.
With this tutorial the author intends to introduce these objects to his audience.

This tutorial explains how the technology behind the mapping process works, and how the game engine knows what it has to calculate. The required background knowledge is included.


The Perfect Level is a ugly Box! Is a Box! A box made of boxes makes a level, not a very pretty level, but in technical terms it is a perfect level.

Each one of these boxes have been created inside the Level-Editor, such a box is called a brush. A Brush can be deformed and reshaped in many ways. In this tutorial we assume that a brush is a square or cubic box, with exactly six surfaces.

To create a brush you need to press the left mouse button and hold it, while you move your mouse in any direction, to determinate the shape of your brush.

A Surface is a single side of an object, our object is a brush, which has because of its geometric shape exactly 6 sides.

A single Brush Surface with a TextureEach surface can only carry a single Texture, this means that our brushes can have up to six different textures; One on each surface.

If we have a brush with six textured surfaces, the game will draw all of these Textures, even those invisible to the player. For example, the outside of our „perfect level“, this makes six surfaces drawn per brush. The player can only see one surface of each brush, that makes 30 unnecessarily drawn surfaces.

The CAULK-Texture is an Image shown in the Level-Editor but not in game. During the compilation of the level into a BSP-File, the compiler marks all surfaces with the CAULK-Texture as invisible. You can load CAULK from the menu of the Level-Editor: Texture -> Common

The Perfect Level from the out-sideHow the „perfect level“ looks from the outside. It is „caulked“, and will not be drawn in game.

NOTE: Older compilers such as Compilers for Quake2 and the first releases of the Quake3 Compilers did automatically mark all surfaces which where on the out-side of a level as invisible as CAULK does, how ever this had certain disadvantages and changed on newer versions.

A texture is an image imported into a game. The texture is a visual cover for a surface, like paint on a wall.

The Perfect Level from the in-side

How the perfect level looks from the inside, it is hermetically sealed.

Some Textures have additional information attached to animate them and/or to apply specific attributes, like footstep-sounds to be used or turning the Brush Contents into semi-solid like water.
CAULK is also one of these special Textures, the additional Information is specified in a SHADER-File.

Textures are loaded into the RAM of the Player its Computer before entering the level, and are un-loaded when leaving the level or loading a new level. They are kept in the RAM when the level gets restarted or reloaded. (in-game console command: restart/map )

Continue on the next page with Chapter: ADDING DETAIL TO „THE PERFECT LEVEL“

Post comment Comments
razorb Nov 28 2009, 1:43am says:

i havent read through it.. but its nice to see people writing tuts for the community :) thank you

0 votes     reply to comment
TheHappyFriar Nov 28 2009, 10:48am says:

nice! Very nice!

This applies from Quake 1 (which didn't have hints or anything similar) all the way to ETQW (which does things differently, but the basics are almost the same).

Great detail & depth. :)

+3 votes     reply to comment
half-life Nov 28 2009, 7:10pm says:

HL1&2 + ep1&2 and most of the quake games feature bsp compiled maps.

+3 votes     reply to comment
Chrissstrahl Author
Chrissstrahl Nov 28 2009, 8:58pm says:

Thanks :)
If anyone has details I'd be happy to put them in.

+1 vote   reply to comment
dany14920 Aug 14 2010, 11:12am says:

I hope this guide will help me with creating a mod and thx:)

+1 vote     reply to comment
Guest May 28 2014, 5:48am says:

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Chrissstrahl Author
Chrissstrahl Feb 24 2015, 4:54pm replied:

I don't have call of duty, but I guess it is pretty similar to Quake3 mapping, you could be looking there for tutorials. This here is a rather technical tutorial explaining the mechanics behind the mapping.

+1 vote   reply to comment
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Quake III Arena
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