Quote from lightOfDay on September 18, 2013, 8:18 pm

I am absolutely horrible at writing tutorials, which is why I'm going to do this in many parts, so I can refine my tutorial. I'm not writing everything all at once, or you wouldn't be able to understand a thing I wrote!

There I a few tutorials like this out here, most notably Darkylight's tutorial. I first learned how to make test chamber signs from his tutorial. By making slight (at least in theory) modifications to his method, I found a new way to make test signs.

These are some pros and cons, relative to Darkylight's method:

Pros
-Fully customizable flicker
-Can be made to look like the "official" sign
-No glare from spotlights
-Self-illuminating texture for even lighting

Cons
-Dynamic lighting is not possible
-Very difficult to set up and implement
-Very difficult to modify for different signs
-Very difficult to set up with custom textures

I must warn you, this is very difficult. It requires advanced knowledge of image editing, textures, and logic entities. I will do the best I can to make it as simple as possible to follow without prior knowledge, but there is only so much I can do.

Before beginning you will need:

-An image editing program. The tutorial is for Photoshop, so you will need to know how to do the actions in your program. GIMP will probably work fine, Paint.NET might take some workarounds.
-VTFEdit, for putting the images in a texture.
-GCFScape, for extracting some textures from the game files.
-Omnicoder's Sign Maker, recommended, but optional if you want to make the textures yourself. This tutorial uses selfillum, so you will also need to know how to make the alpha channel for you custom texture.

Once you have the above things installed, you are ready to go.

Read This First!
[spoiler]The both the texture and the images used to make it are reffered to as "textures". The individual "textures" are reffered to by number in the tutorial. The textures, when complete are:

Texture 0: Black (Uses elevator screen texture)
Texture 1: Dim, with no numbers, bars, or icons
Texture 2: White, with no numbers, bars, or icons
Texture 3: White, with no bars or icons
Texture 4: White, with no icons
Texture 5: White

You don't have to use all of the textures. The example flicker in the tutorial does not use Texture 2 or 3. You may want to follow the tutorial through, and then use all six textures to create a flicker, and finally remove the textures you didn't use in your flicker.[/spoiler]
The Tutorial
[spoiler]TODO: Add Texture Fetching
TODO: Add Pre-Pass Filtering
TODO: Add Image Editing
TODO: Add Texture and Material Creation
TODO: Add Entity Setup
TODO: Add "The Way Valve Does It" Section[/spoiler]

Enjoy!