In addition to the default textures, material-textures (that's how I'm calling it) produce particular sounds when stepped on, shot, and hit by melee, as well as drawing other particles and decals, depending on their type.
You can view the complete list of these "special textures" predefined by the game in an arranged HTML file included in this download.
A Tutorial on how to assign a material type to any custom texture is also included in the HTML file.
Games that exclusively make use of this feature are:
- Half-Life: Opposing Force
- Counter-Strike: Condition Zero
- Counter-Strike: Condition Zero Deleted Scenes
- Day of Defeat
The included sample maps consist of 64x64 brushes previewing the material-textures in each of these games. In both the maps and HTML, the entries are organized by material type and alphabetical order.
Note: No WAD file is included. In order to view the textures, you need the WAD of the respective games.
Make good use of it.