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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 2 of 10    
Basic Mapping/Technical.


The Perfect Level-DetailOur „perfect level“ looks a little bit empty, to keep this simple I will place a box in the center of the map.

I have now created a cubic brush and applied the same „texture“ on each of the five sides, the sixth side is facing the floor and can't be seen, and is suppose to be solid, so I applied CAULK on it!

The Picture on the top right of this chapter shows a „perfect detail“ inside a „perfect level“, but the box seems to be sick. Why else should it be highlighted green instead of red when selected?

Here is the answer why the box is green: The Editor highlights selected brushes in different colours when they have different functions. This box is drawn green because it is not a regular brush, this box is declared as „detail-brush“.

I will introduce you now the ÜberRadiant, it is the level editor for Star Trek: Elite Force II.
The ÜberRadiant can be set up to have one 3D and three 2D views, this is how I work with it and how I will introduce it to you!

The Überradiant for id-Tech 3 with Rituals Übertools

To declare a brush as „detailed-brush“, de-select all other brushes, press ESCAPE and select the brush you want to turn into detail.

Now you need to click on one of the 2D-Views and press the right mouse Button, then select „Make Detail“.
How to turn Structural into Detail

Alternatively you can use a keyboard short-cut, to make a brush to a level-detail. If you work with the ÜberRadiant you can press CONTROL, hold it and press then SHIFT, hold that too and finally press the key D.

If you have not broken your fingers with the key-combination CONTROL+SHIFT+D, you can release these keys now. The brush changed its highlight colour from red to green, which means that the brush changed its functionality. This brush is now a „detail-brush“, used only to decorate the level.
You will learn now why this brush had to be turned into a „detail-brush“, and what that means.

A Example for using detailed-brushes

The ugly Ferengie on this image represents a player in game.

According to his Field of View (FOV) the ugly Ferengie is able to see the Box, and the most of what is behind the box.

The id Tech 3 engine can blend out parts of the level which are behind a „structural-Brush“, we go into detail later.

This blending-out and blending-in, requires a few additional calculations. These calculations will slow down the overall calculation process of the game, this means it will render less of the level over the same amount of time. Your Frames per Second (FPS) will drop for a short time.

In the Image shown above, it would be very un-wise to blend this „Black Invisibility Triangle“ area behind the box out. It would take a very little move in any direction for the player to change the the „Black Invisibility Triangle“ area. The box would produce a blend-in, blend-out minefield.
I have shown you just one box as example, but imagine a room with 100 or even more boxes. This would drop the FPS of every player moving along or near by these boxes.

A straight view through the detailed-brushOnce the box is a „detail-brush“, the FOV goes straight through the box.

The game will calculate and draw now all objects behind this box. If there is a small object behind the box, the textures of the box do completely overlay it and the player can't see the object behind the box anyway, but it is still calculated and drawn.

Using the ÜberRadiant, you can blend out all „detail-brushes“ of your map in the Editor-view at once, by using the key-combination CONTROL+D. Use CONTROL+D once again to show the „detail-brushes“ again. It is highly likely that your Level-Editor offers such a feature, perhaps with a different key-combination.

Level-Editors usually shows a fine grid in the 2D-Views, this grid represents a specific amount of units. Pressing the 0 (Num-Key) on the Keyboard, hides/shows this grid in the most Level-Editors.
To zoom in or out, left click once into one of the 2D-views and scroll with your middle mouse button.
The grid in the selected 2D-View will change and apply to the next higher or lower grid resolution.
Select the finest grid by pressing the Number 1 on your Keyboard, fully zoomed in this will show blocks of the size of 1*1*1 unit. If you now create a brush you will start with a block of 1³unit.

Units define the size of objects, as for example in Elite Force II, a player has the following set of units; When standing: Width 44, height 108, when crouching: Width 44, height 49.

The scale for the units, to build levels in STEF2 is different from other id Tech 3 based games. STEF2 uses a unique BSP-Tree specification, which means that the (compiled) levels are not compatible to other id Tech 3 based games.

The Frames per Second (FPS) tell you how many times the game has been drawing the level within one second. 60 FPS means that the Game has been showing you 60 continuously updated images of the level.

Continue on the next page with Chapter: ENTITIES

Post comment Comments
razorb Nov 28 2009 says:

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

+1 vote     reply to comment
TheHappyFriar Nov 28 2009 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 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 says:

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

+1 vote   reply to comment
dany14920 Aug 14 2010 says:

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

+1 vote     reply to comment
Guest May 28 2014 says:

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Chrissstrahl Author
Chrissstrahl Feb 24 2015 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.

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