Subtraction
Simple Subtraction of Brushes

Note that this tutorial simply explains the process for subtraction.  To learn more about why it works and how to use it more effectively, continue to the Adding tutorial.

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  1. Open UnrealEd.  You should see three gray mini-windows with darker gray lines in them and one black mini-window with blue lines in it.  The black window is the 3D viewport, and the gray ones are the 2D viewports.
  2. Select the red Builder Brush in any of the viewports by left-clicking on it.
    ***NOTE*** If there is not a red square or cube visible in any of your viewports, click on the cube-shaped button on the left-hand side of your screen (it's next to a lot of other shapes).  This will be discussed in the next section.  If you can't find the button, click the arrows at the tops of the toolbars on the left to expand them until you find the right one.  I believe it's the toolbar that's second-to-top.
  3. Hit [ctrl] + [s].

If you move the builder brush (select it, hold [ctrl] and left-click-and-drag) you will see a yellowish brush in the same shape as your builder brush.  This yellow color means subtraction; the color can be changed on a per-brush basis, but you probably won't want to.

In the 3D viewport, you should now see three sides of your cube with an ugly bubbly texture on it.  If you navigate closer, you can enter the cube and when you look around you'll see all 6 sides.  This is an important aspect of UEd--there is no "outside," so when you're in solid space you can see right through the "walls" of rooms.

All of the space you run around in in UT is, at least initially, carved out of subtractions.  Note that the most recently inserted brush will be considered by the BSP calculator last, which means if you subtract a room, then add space back in, the added space will appear because it was calculated after the subtraction.  If you had added the space, then subtracted the room, the room would have no additions in it because the subtraction would have been applied after the addition.

Top | Back to Navigation | Up to Your First Level directory | Continue to Adding
Home | UT2004 Tutorials | Key Terms | Multiplayer Design