Creating A Space
The most important things with a map is that there is actually a subtracted space where the players can move around.
By following this tutorial you will learn how to create such a space in two different ways.
Good to know tip:
A player is about 96 units tall, and 50 units wide.
First of all you probably already have your editor open and are ready to try the things you will be told to here.
If not try to look for your UT3Editor in: Start - All Programs - Unreal Tournament 3 - Unreal Tournament 3 Editor if you cant find it, try looking in the root folder of your installed game.
1. Click File - New (or click on the icon of a blank piece of paper) in the upper left corner of your screen.
2. Now you will have to choose the geometry style of your level. Additive means that there is already a huge space and you build your map in it, so if you want this style just "Click additive and OK" and you have a subtracted space. In other words, for additive levels you would now already have a subtracted space and you are done. (Still even in additive levels you most likely need to know how to subtract spaces, so I would recommend following the subtractive way of this tutorial.
If you want a subtractive level where everything is already a huge filled space and you create rooms inside. This may seem like a worse way but it can be quite useful most of the times, but is still depending on the map you want. Click Subtractive and OK.
3. Now that we have a new map open you right click the "Cube" icon, in the left menu showing many fancy green icons.
4. Then now we can set the size on our cube in the X, Y, and Z axis.As for now we can enter in "X=512, Y=512, and Z=256" then click "Build"
5. now click CSG:Subtract. Find it in the left menu.
6. Now your 3D view should have been surrounded by some chess looking thing. If not, you can attempt to move your 3D camera, using the mouse. Rick click=Forward and turn. Left Click=Turn all directions. Both=Move camera up/side. Move a little around in your hollow cube and try 2 get the hang of it.
Congratulations, if you did this correctly, you now have a hollow space where you can fool around.
Discussion
Raven: Testing that I have done seems to indicate that a subtractive world is not as efficient as a additive world. Does anyone else get this drop in frame rates using subtractive?
MythOpus: Well as far as I know games like FEAR and the Half Life series all use 'additive worlds' and while the majority of it is related to lots and lots of optimization systems, framerates are pretty wonderful considering how much stuff they put into a scene at a given time. On the other hand UED has been using the 'subtractive' world afaik straight from the release of Unreal 1 so I don't think they would have avoided Additive game worlds if they thought 'subtractive' game worlds were worse. Just speculation of course.
MrVortex: Well I suppose it is mostly depending on the map you want to make. For things like space and such I use additive, while I use subtractive for cave like maps. Both can be useful to know.