Path to an art file (typically .pcx or .bmp) used to guide the mapping of shaders onto a metashaded surface, such as Quake III: Team Arena-style terrain.
The path for _indexmap should start in the same directory as is used by your game's fs_basepath switch (i.e. "baseq3"). If your indexmap were found at "C:\path\to\Quake III Arena\baseq3\indexmap.pcx", a value of "indexmap.pcx" for the _indexmap key would be sufficient.
_indexmap used to be "alphamap", though the latter is now deprecated. A key of "alphamap" will still work, but (as it does not follow the underscored compiler key format) its use is not encouraged.
Floating point value scaling the resolution of lightmaps on brushes/patches in this entity (default 1.0). A _lightmapscale of 0.25 would result in four times as much lightmap detail as 1.0, while 4.0 would only have one quarter of 1.0's detail.
_lightmapscale is used on func_group entities; though worldspawn supports _lightmapscale, use of lightmap scaling on the world is not recommended.
Sets the autoclipping spawnflag, automatically assigning q3map_clipmodel to any shaders used by the model.
Use of Q3Map2 autoclipping for models is only recommended for large models with relatively few triangles in their mesh (i.e. terrain). The Q3Map2 autoclipping algorithm is a bit of a hack, and can hurt in-game performance (as well as produce erroneous clipping results) when used on small, dense models.