WiseDispCorner: Rounded interior corners
This tutorial was originally created by wisemx. It was originally posted on SDKnuts.net.
(Porter's note: This is another tutorial I personally do not think was worth making/should be followed. Anyone else may format it if they so please, but I'm just pasting straight in.)
Contents
Introduction
In this project, we’re going to create two types of rounded wall corners:
- The first will be from normal brushes using the Clipping tool. (Can be converted into a
func_detailfor optimization) - The second will be from multiple brushes converted into displacements. (Looks nicer)
I’m only going to make one cut on the first brush with the Clipping tool to illustrate that a nice appearance can be had inexpensively when optimization is a challenge, but you can do a lot more with multiple brushes in the same corner and some final Vertex editing,
Note:The download for this project has saved stages in several 
vmf files, for practice.Creation
Note:Make sure Snap to Grid is on.I’ll start with this blank room:
In the image above the concrete textured brushes will become displacements. The orange Dev textured brushes will be Clipped.
Notice the placement of the brushes. The ones that will become displacements are arranged corner to corner. The ones that will be Clipped are simply placed in the corner where other brushes meet.
Creation with the Clipping tool
1) Select the brush.
2) Zoom in on the selected brush in the Top 2D viewport.
3) Select the Clipping tool. Shift+X
4) Draw a line diagonally across the top of the brush.
5) Make sure the Red lines are on the side to be removed, if not click the Clipping tool icon again until it is. (There are three modes)
6) Press Enter to remove the part in Red.
7) Do the same for the other brush or clone the first brush and rotate the clone.
To clone a brush hold Shift as you drag a copy in the 2D view ports.
Creation with Displacements and Subdivision
1) We start with a set of brushes that meet like this at their corners.
2) It’s important to size these brushes properly as the rounding from the Subdivide tool will consume a lot of the brush. The height of your brushes will be determined by their purpose but you may need to experiment with the width.
3) Move these brushes away from the map once they are sized.
(This is often best done in the Top 2D viewport.)
4) Make clones/copies of these brushes until they are surrounded by copies on all sides.
5) In the image above you can see the original two brushes in the center.
There are now a total of 12 brushes being used for this corner, 10 of which are temporary. They will be deleted soon.
6) Open the Face Edit dialog (Shift+A), switch to the Displacement tab and hold Ctrl as you left click on each of the inter faces for these 12 brushes.
Don’t select any edges, just the inside faces.
7) Click the Create button and choose "Power of 3".
8) Now with those 12 Displacement faces still selected click the Subdivide button.
9) Delete all of the brushes we just created except for the center two original brushes, which will now be shaped perfectly.
10) Move these two remaining brushes back into place and you’re almost done.
11) We’re almost done because we need to seal behind these displacement corners. Normal brushes textured with nodraw are what we’ll use.
If you want to know what would have happened if we didn’t use the extra brushes that were deleted create the same corner without them, what you’ll get will look like it got hit by a Truck.
These are shots of the final in-game effect. (Looking up at the Skybox ceiling)
Clipped corner:
