Advanced Light, ZHLT and Vluzacn's keyvalues. Sven Co-op FGD includes those keys in entities that support ZHLT keyvalues. ZHLT keyvalues are resolved at compile time to alter light settings or add special effects to improve lightning on your map. More info about ZHLT/VHLT compile tools can be found here.
Minimum light level _minlight : Brush entities only, supports value '0' for default, and '1' for full brightness on this entity. This is useful when you need textures of this entity be always visible by ignoring the light level e.g. computer screen in the darkness or hologram. Similar effect for models in point entities can be achieved by setting "Render Mode" to "Additive".
ZHLT Template Model Target zhlt_usemodel :
ZHLT Copy Lighting From Target zhlt_copylight :
ZHLT Disable Clipping zhlt_noclip : Enable or disable collision of entity. Use it in case when entity have no build-in collision disabling ability (e.g. by selecting "Passable" flag in func_door) and you much desire to disable collision for this entity.
ZHLT Light Flags zhlt_lightflags : Brush entities only. Changes light casting or receiving setting.
ZHLT Light Origin Target light_origin : Brush entities only. Set it to the name of info_target, this entity will receive lights from specified info_taget position instead of it's own position. As a lot of entites can moves and lightning is not updated dynamically you can choose how your entity will be lit in game (e.g. elevators, pushables e.t.c.). Now you don't need to put the whole entity in the well-lit room at map start to make them look desirable.
ZHLT Invisible zhlt_invisible : Brush entities only. Determines if entity should be visible.
ZHLT Custom Shadow (when opaque) zhlt_customshadow : Opaque brush entities only. If "ZHLT Ligth Flags" of this entity uses any of the option with "Opaque" word, this will allow to customize shadow dropped by this entity. Value format: [0 - 1.0] [0 - 1.0] [0 - 1.0], use three values for color or only one for transparency:
ZHLT Embed Light Map (when translucent) zhlt_embedlightmap :
Transparent brush entities only. Set it to 'Yes' and this transparent entity will take a light from environment making it looks much more natural. Use it when entities (e.g. glass represented by func_wall) omits lightning from surrounding. Note that this is expensive so shouldn't be used too often, but resolution of those lightmaps can be controlled by keyvalue explained below.
ZHLT Embed Light Map Resolution zhlt_embedlightmapresolution : Value of power of two that controls the resolution of embedded lightmaps of transparent textures (see keyvalue above). Higher value for better optimization. Default and recommended value is 4.