The Sith Engine, a creation of LucasArts, served as the foundation for the game Star Wars: Jedi Knight: Dark Forces II. A slightly enhanced iteration of this engine powered its expansion, Star Wars: Jedi Knight: Mysteries of the Sith.
Modified and updated versions of this engine also appeared in Star Wars: DroidWorks, the Star Wars: Episode I The Phantom Menace video game, and Indiana Jones and the Infernal Machine.
Additionally, it was integrated into the GrimE engine for use in Grim Fandango.
The engine lacks support for transparency on a per-color basis and offers anti-aliasing comparable to that of the Nintendo 64. Despite this, it renders efficiently. However, the background environment and the first-person perspective gun are typically rendered on distinct layers. The background was rendered at 30 FPS, while the gun's rendering had no framerate limit. While this didn't pose issues during gameplay, the increased power of modern computers often causes on-screen weapon animations to play too rapidly, due to their increased processing power compared to the computers of 1997.
3do files represent the 3D models utilized by the original Sith engine. Each file encompasses texture definitions (referred to as MAT files) alongside text data specifying mesh names, vertices, faces, shading methods, and similar information. MAT files consist of converted 256-color bitmaps. These bitmaps are restricted to rendering as perfect squares divisible by 8. Given that consolidating all textures into a single file was impractical (until more recent approaches for assigning textures to fan-created 3do models emerged), each individual body part features a unique texture. In certain instances, textures are reused.
Animations for the 3do models are sourced from files designated as KEY files. Despite sharing the same extension as Windows registry files, they are fundamentally different. KEY files serve as animation definitions, containing every frame of animation sequences for both player characters and enemies, and occasionally even flight paths for ships. Extensive modifications to KEY files enable the creation of entirely new character motions, although in some cases, enemy KEY files and player KEY files are not interchangeable.