OBLIGE is a random level maker written by Andrew Apted for Doom, Wolfenstein 3D (no longer planned for version 3 ), Heretic, Hexen, and Quake (since version 3.57). It features a GUI interface, scripting language and prefabs, ability to create deathmatch levels, etc.
OBLIGE is considered a step up from Slige; OBLIGE creates more compelling architecture and has a number of features Slige does not have, such as:
- Real outdoor areas
- Heretic, Hexen and Freedoom support
- GUI used to build levels
- Monsters in cages
- Instead of being written entirely in C, the Lua scripting language is used for the majority of level creation code.
Since the bulk of level creation code is written in Lua, it is possible to modify and customize the random map generator without needing to recompile the GUI shell for OBLIGE.
This has resulted in a number of customizations to OBLIGE being released, including Mr. Chris' customizations that, among other things, add Skulltag support to OBLIGE, and Sam Trenholme's fork of OBLIGE version 2, ObHack (which has support for secret areas and more customization options in its GUI than OBLIGE).
 Versions of OBLIGE
 Version 1
- Never released to the public, offered only basic level building capabilities.
 Version 2
An overall obsolete version that does however have some features not available in version 3. Last released version in the branch was 0.97.
- Full support for Doom and Doom II, ability to create functioning Heretic and Hexen levels. Buggy but working support for Wolfenstein 3D.
- Caged monsters
- Prefab system
- Secret levels
 Version 3
The current and latest released version of OBLIGE, which is no longer being developed. Last version in the branch was 3.57.
- Doom, Doom II, Heretic, Hexen and buggy Quake support.
- Bigger rooms and more complex architecture
- Modular support for custom content such as Skulltag support
- Faster node building
 Version 4
A work in progress version of OBLIGE that is aimed for replacing the current 3.xx branch of OBLIGE. A wide array of features is planned for this version, including:
- Doom, Doom II, Final Doom, Heretic, Hexen, Quake and Quake II support.
- Prefab system
- Caged monsters (feature present in version 2 but not in version 3)
- 3D floors for Quake, Quake II, and some Doom source ports (GZDoom, Legacy and EDGE methods of defining them are supported).
- Power-ups such as berserk packs and invulnerability spheres (not implemented yet)