maps that are outdoors rather than Doom and Quake, which are optimized for indoors. It utilizes a pseudo-3D world model similar to the Doom engine, based on a 2D height map. This imposes some limitations (e.g. no rooms above rooms), but does permit slopes and 3D props, which in turn can be used to make up for most limitations, for example, to create bridges with a passage below. The engine is based on zero-precompilation philosophy—all map data is interpreted dynamically, with no need to recalculate such as shadowmaps or BSP data. This makes realtime in-game map editing feasible. Cube supports multi-user, realtime map editing. The engine is compact and relies on simplicity and brute force instead of fine-tuned complexity. Further development Engine The engine was reused for several other games, the developers usually modified the engine to adapt it to the needs of their projects. However, there also are changes of unclear nature. The main reason for this is that the engine code is not clearly separated from the game code. Such changes of unclear nature appear both in mods of Cube and in other games using the Cube Engine. When the engine is modified, the changes tend to be minor but there also are cases where the changes are significant, such as in AssaultCube (released in November 2006) and its fork AssaultCube Reloaded (released in December 2010). Ports Intel ported the game to OpenGL ES to demonstrate a new mobile 3D chipset at the Game Developers Conference in 2005. A Cube port, intended as a technology demo was submitted to the iPhone in 2008, and was released to the iPhone App Store on November 18. A version of AssaultCube for Android was released in may 2021. Successors (other engines) Cube 2 Engine Cube 2: Sauerbraten, released in 2004, is the official successor of Cube. It uses an other engine, the Cube 2 Engine. Even if the earliest revisions of Cube 2 Engine were based on the Cube Engine, it became with time very different. There are many differences between the Cube Engine and the Cube 2 Engine, including two major ones. One of these two major differences is the geometry. Unlike the Cube Engine, that has a 2.5D geometry, the Cube 2 Engine has a real 3D geometry. The other of these two differences is the fact that the source code is foldered. The code of the engine and