1. Hammer Shortcut Keys
2. Working with Different Views
3. Clipping and Resizing

Adding a Room

Now comes the fun part. After you've ungrouped the original room, you can edit each of the walls separately. Click on the wall to the left of the counter-terrorist spawn entity, and press the Delete key on the keyboard. That wall should disappear.

Next, make a new room adjacent to the original one. Make sure your grid system is set to 32 first. Create a new cube first by using the Block Tool and dragging out a larger brush along the North side of the original room. Let's make this room 608 x 768 from the top (x/y) view. Adjust the height of the room from the y/z view if necessary, but I found that Hammer is usually smart enough to automatically make the height the same as the adjacent room. Your map should look like the one below:

Creating an adjacent cube

Now, hollow out the new cube as you've done before (Ctrl-H; set the wall thickness to -32), then ungroup it as you did previously in this lesson (Ctrl-U). Select the wall that is adjacent to the original room.

New room with wall selected

We're going to use the Clip Tool Shift-X to cut out an opening in the wall so that the two rooms are connected. With the wall still selected (it should be red), use the Clip Tool to cut along the wall of the original room. It's most easily done from the top (x/y) view. Drag your mouse across the wall and release, half of the wall should have a thick white border and the remaining half still looks red.

Clip Tool step 1

Now, press Shift-X again. You'll notice that the other half of the wall now has this thick white border in the 2D view. Press Shift-X once again, and both halves are white, with a thick white dividing line through the middle.

Clip Tool step 2

Press Enter to make the cut. The wall is now sectioned into two. It's sort of like ungrouping a brush, where you generate multiple brushes from one.

Now, select (press Shift-S) only the part of the sectioned wall that's blocking the original small room, and resize it. You resize a brush by dragging those white square handles that appear around the brush when you select it. We want to reduce the brush so that the wall isn't blocking the connection between the two rooms.

Resizing a brush

Click anywhere outside of the map to deselect the wall, and fly around in the 3D camera view to admire your handywork. Pretty, ain't it? Well, not quite. There is a small problem we have to fix before we're done.

Notice the small area in the ceiling and floor bordering the two rooms? As you move around in the 3D view, it flickers around. This is because the there are overlapping brushes. More than one brushes are occupying the same space in your map. This doesn't look good in-game.

So we need to select the floor and ceiling of the smaller room, and resize them so that they are not overlapping with the floor and ceiling of the larger room. Look closely at the junctions between the walls and the floor/ceiling at the screenshot below. I hope you know how to do this by now. The result should look like this:

Prevent overlapping brushes

Final Touches

So, is that it? Not quite. The large room must be pretty dark, considering that the only light entity in the map is in the small room. We're going to put a light in the larger room too. However, we're going to be sneaky and use a shortcut instead of placing a new light entity from scratch.

Select the light entity first, and Shift-drag the light in the x/y view to the center of the larger room. You should have duplicated the light entity.

Duplicating the light entity

And lastly, we will add a wall in the larger room for good measures. Remember, we don't have to make a brush from scratch. We will just duplicate a wall by Shift-dragging an adjacent wall and then resizing it, like so:

Duplicating a brush

Are we eager to compile this sucker? Don't forget to save it first (Ctrl-S). I hope you have been saving all along, like me. You wouldn't want to lose all your work because of a power surge, wouldn't you? And let the glory unfold with one tap of F9!

Final screenshot

If you still have the strength and energy, we'll move on to texture our map in the next lesson.