Undefined is a Level Theme in various Quake Add-ons. Similar to Common, this is an unofficial Level Theme created to categorize other Level Themes. Undefined refers to any Level Theme without an official name.
Often, commercial Add-ons included their own level theme to avoid copyright issues. While levels could be created for free without issues, commercial levels were debatable, and therefore the Add-ons took to using their own textures. This resulted in their own "theme", where all the levels would interchange the textures without the exclusivity found in the original game. This means that, in most cases, the levels didn't have the sort of variation that an idBase level would have with a Medieval.
- Aftershock Level Theme
- Aftershock Toolbox Level Theme
- Beta3 Level Theme
- Dark Hour Level Theme