Cake is powerful 3D game engine and (as a reference application) map viewer
for id Software's Quake III Arena maps.  It currently features:

    * BSP (+PVS) support
    * Collision detection (with normal faces + patches)
    * Shaders and textures
    * Lightmaps and models
    * Vertex deformations
    * Cloudbox and skybox (nearbox/farbox)
    * Volumetric fog
    * Bezier surfaces (with variable LOD)
    * Multiple viewports
    * Console
    * Record/playback demo support (DM3 format not supported)
    * Background music + 3D sounds (not under FreeBSD though)
    * Entities (with variable LOD)
    * ZIP compressed files (*.pk3)