Material map compile flags

Several special shader parameters exist that start with a % sign instead of $. These are read by the compile tools to alter the properties of the face or the brush they are attached to. Most are intended to produce the special tools/ textures, but they may also be used for other materials.
All flags are boolean properties and invisible to players. So far %CompileLadder is the only flag which may be visible to players, depending on the proxies inside the material. %CompileTeam Is also the only flag that is not a boolean.

See also Tool Textures for more detail about the propeties of individual materials.

Example:

LightmappedGeneric
{
 $basetexture developer/custom_clip
  %compileclip 1
}

Note:As with shader parameters, the names of compile flags are not case sensitive: %compileclip 1 and %CompileClip 1 deliver the same result.

Note:These flags are associated with contents and surface flags which are stored in the BSP can can be stored in the VMF; see BSP flags (Source) for more information.

Todo: DeathByNuke's VBSP has %CompileChopLow, %CompileChopHigh, and %CompileChopAll, which affect how brush faces are spilt when touching other brush faces; document these.

Exclusive Flags

Only one of the following flags may be set on any given material.
Every flag is available in all Source Engine branches, unless specifically mentioned in the Availability box

Clips

VMT flag	BSP flags assigned	Seen in VMT(s)	Availability	Description
%CompileClip	CONTENTS_PLAYERCLIP CONTENTS_MONSTERCLIP SURF_NODRAW SURF_NOLIGHT	toolsclip		Makes the brush block only players and NPCs. This is equivalent to a combination of %PlayerClip and %CompileNPCClip.
%CompileNPCClip	CONTENTS_MONSTERCLIP SURF_NODRAW SURF_NOLIGHT	toolsnpcclip		Makes the brush block only NPCs. This implies NoLight and NoDraw. Note: Blocks bots, even though they are players.
%PlayerClip	CONTENTS_PLAYERCLIP SURF_NODRAW SURF_NOLIGHT	toolsplayerclip		Makes the brush only block players.
%CompilePlayerControlClip	none	toolscontrolclip	(removed since ) (also in )	Unsure as to how this was meant to be used. Usually seen together with func_vehicleclip. Material also uses $surfaceprop player_control_clip.
%CompileGrenadeClip	unknown	toolsgrenadeclip	(only in )	Makes the brush only block grenades.
%CompileDroneClip	unknown	toolsdroneclip	(only in )	Makes the brush only block drones.

Other

VMT flag	BSP flags assigned	Seen in VMT(s)	Availability	Description
%Compile2DSky	SURF_SKY SURF_SKY2D SURF_NOLIGHT	toolsskybox2d		Makes the face render the 2D Skybox only, in addition to emitting light_environment light.
%CompileFog	none	ToolsFog		This may be a deprecated flag that so far has not been seen as being useful.
%CompileHint	SURF_NODRAW SURF_NOLIGHT SURF_HINT	toolshint		Makes the face hint-cut visleafs. This implies NoLight and NoDraw.
%CompileNoChop	SURF_NOCHOP			Prevents subdividing patches on the surface for lightmapping ("chopping"). Also affects how the face is converted to triangles. A brush face using a material with this parameter will be limited to 31x31 luxels.
%CompileNoLight	SURF_NOLIGHT	nolight	(in all games since ) (also in )	Disables generating lightmaps for a brush face. Useful for materials that don't need lighting info or are always invisible. This is disabled on water materials. Confirm:Is this necessary for UnlitGeneric materials? Important:No effect in Hammer++ lighting preview.
%CompileOrigin	CONTENTS_ORIGIN CONTENTS_DETAIL SURF_NODRAW SURF_NOLIGHT	toolsorigin		[ Deprecated] Sets the origin of a brush entity (origin KV), for purposes such as rotation. Leftover from ORIGIN in . Still functional, but is no longer necessary, as the origin KV is acknowledged by VBSP and can be visualized directly in Hammer 4.x.
%CompileSkip	SURF_NODRAW SURF_NOLIGHT SURF_SKIP	toolsskip		Removes the face during compilation, making the brush into sets of planes.
%CompileSky	SURF_SKY SURF_NOLIGHT	toolsskybox		Makes the face render the (2D/3D) Skybox and emit light_environment light.
%CompileTrigger	SURF_NOLIGHT SURF_TRIGGER	toolstrigger		Makes the brush suitable for Triggers. Implies %CompileNoLight. If -nodrawtriggers is used, also assigns SURF_NODRAW.

Additive Flags

Multiple of the following flags may be applied to any given material.
Every flag is available in all Source Engine branches, unless specifically mentioned in the Availability box

Name	Seen in .vmt	Availability	Effect
%CompileBlockLOS	toolsblocklos		Makes the brush block only the line of sight for NPCs. Note:Also works for bots in .
%CompileDetail			Forces the brush to no longer cut visleafs, similar to func_detail.
%CompileInvisible	toolsinvisible		Makes a surface behave like NoDraw, but still allows bullets to pass through it, except in Counter-Strike: Global Offensive. This also implies NoLight.
%CompileLadder	toolsladder		Makes the brush usable as a ladder, without needing to be tied to func_ladder. Can be applied to any material, such as metal/metalladder.vmt for a cheap ladder without a prop. Else also add %compilenodraw to make it invisible.
%CompileNoDraw	toolsnodraw		Makes a brush behave like tools/toolsnodraw.
%CompileNonSolid			Makes the brush not solid to anything. Bug: Turns brushes non-solid and invisible but still casts shadows.  [todo tested in ?] Tip:Analogous to NOCLIP tool texture in GoldSrc (ZHLT, VHLT, and derivatives)
%CompileNoShadows		(only in ) (also in )	Prevents shadows from being cast onto the texture.
%CompilePassBullets			Makes the brush behave like a grating, allowing bullets to pass through but blocking other objects. Useful for foliage or metal grates. Note:Allows explosions through, but not bullets in . Bug:Non-functional in Counter-Strike: Global Offensive and Counter-Strike: Source.  [todo tested in ?]
%CompileTeam	climb_versus	(only in )	Decides which team should be affected by this tool texture.
%CompileWater			Marks the brush as a water-type material. Makes it non-solid, allows swimming inside, etc. If %CompileKeepLight is also set, the brush will retain its lighting data.
%CompileSlime			same as %CompileWater, but with green splash particles. Bug: %CompileSlime uses default water splash particles.  [todo tested in ?]
%NoPortal	toolsblack_noportal	(only in )	Makes the texture non-portalable unless Conversion Gel is used.
%NoPaint		(in all games since )	Makes the material unable to be painted by Gel. Implies $nodecal, as they share a surface flag.
%CompileStairs	toolsstairs	(only in )	Makes brushwork traversable up to an angle of 63.4349488, as opposed to the usual 45°.
$NoDecal			Makes the material not receive decals. Important:This is a map compile flag when used on brushes and displacements, but not when used on models, hence why it starts with $ instead of %.