csg.txt

quake的地图编辑器的源代码, 不是quake3的

 - Brush CSG Subtraction!  Here's how to use this:

    1. Select the brushes you want to subtract 'from'. They will be 
       smashed, split, cut, however you want to say it.
    
    2. Hit 'i'.
    
    3. Select the brushes you want to subtract 'with'. They will do 
       the subtracting and remain unchanged. After the subtraction,
       these brushes will remain highlighted. So if you wanna get rid
       of all of them, just hit the delete key after subtracting.
    
    4. Right-click.
    
    5. Poof! The subtraction has been done.

 - Brush CSG Intersection!  This is similar to the subtraction concept,
   but in reverse.  It creates a brush that is the space that the
   two brushes have in common.  The easiest way to see what this does
   is to use it on two brushes that are intersecting.  Anyway, here's
   how to do it:

   1. Select two brushes.  Order doesn't matter.
   2. hit 'o'.
   3. Poof! The intersection brush has been created.