One of the most basic functions a mapper must perform is the simple act of cutting up brushes. In particular, cutting holes in existing brushwork seems to confuse many novices. What is the best way to do it? This may seem a silly thing to create an entire tutorial on, but I assert that it is vital for your future mapping career. Every sloppily made doorway or window becomes a future headache as you refine and polish your creation. Unless you learn to do it properly every time, you will always be limited to simplistic maps.

I will begin by showing you the correct way to do things (clipping), followed by a discussion of the alternate technique (carving) and why it is inferior.

So, you have a room, but no way out. The time has come to cut a door.

1. Select the wall brush, and select the clip tool (Shift+X).
   
   
   
   
2. Left click where you want the cut to start and drag just like as if your cursor was a knife. Release the left mouse button when you are satisfied. Note that you can move either end of the cut as you will. It should look like this:
   
   
   
   
3. Note that half the brush is red and half white. If you press ?enter? now, the red part will be deleted. As we do not wish to delete any portion of the brush, press ?Shift+X? until both sides of the brush are white.
   
   
4. Press ?enter? and the cut will be made.

I have just created one edge of my door. Repeat this step on the other side so as to create the width you want, and then clip or transform the remaining piece that fills the ?doorway? as desired. My finished product looks like this:



That is the correct way to make a square opening. You ought to be able to adapt these techniques to any hole you might wish to make. But, you say, why not simply make a block the size of the door you want and carve away? Let?s try it.

This is what you get:



Now, this is not such a bad result. However, there is a subtle difference. The carve tool has split my wall brush down its long axis. This has three distinctly negative effects. First, it will make brush manipulation more complex down the road should I ever want to change this wall in any way. Second, it clutters the view more than does the clipping method. Third, and maybe most important, it is likely to increase the poly count of my wall. Because of the way the compile tools split up world geometry, brushes with wide aspect ratios are more likely to unduly increase poly counts than those that are close to 1:1. This of course depends on the exact dimensions we are talking about, but I?ll not get into that. The increase in manipulation difficulty and view complexity may seem paltry, but I can assure you it is not. When your maps become complex enough, every little bit of simplicity you can hang onto is worth its figurative weight in gold.

(You should also note that carving will often mess up texture alignment, as well as the above- Lep.)

But, you say, these are awfully stingy benefits to warrant something as unduly complex as clipping! Not so. Let?s see what happens with a more complex case. Eventually I hope that four sided polygons will begin to bore you. You will want to do something more artful. Let?s try making a round window with the carve tool. This is the result:



I can hardly imagine a worse way to split the brush. You will never get of the ground with this kind of brushwork. Heck, in some cases, your map won?t even compile.

These are the results you get from clipping:



Much nicer, you must agree, and it really doesn?t take significantly more time. In the long run, you will save it ten times over in the ease of later manipulation. The bottom line is, the carve tool is evil. You?ll notice I didn?t say anywhere how to use it. If you don?t know already, you?re better off remaining ignorant.