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.
Most flags are boolean properties, except where specified.

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.

Todo: Separate page that documents Source 2's VMAT attributes, which is successor to compile flags.

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 removes SURF_BUMPLIGHT	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 removes SURF_BUMPLIGHT	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 removes SURF_BUMPLIGHT	toolsplayerclip		Makes the brush only block players.
%CompilePlayerControlClip	CONTENTS_DETAIL CONTENTS_MIST SURF_NODRAW SURF_NOLIGHT removes SURF_BUMPLIGHT	toolscontrolclip	(removed since )	Unsure as to how this was meant to be used. Usually seen together with func_vehicleclip. Material also uses $surfaceprop player_control_clip.
%CompileGrenadeClip	CONTENTS_DETAIL CONTENTS_GRENADECLIP SURF_NODRAW SURF_NOLIGHT removes SURF_BUMPLIGHT	toolsgrenadeclip	(in all games since )	Makes the brush only block grenades.
%CompileDroneClip	Confirm:Probably like %CompileGrenadeClip, but with CONTENTS_DRONECLIP instead of CONTENTS_GRENADECLIP.	toolsdroneclip	(in all games since )	Makes the brush only block drones.
%TeamClip	Confirm:Probably same as %PlayerClip, but with the addition of CONTENTS_TEAM1 or CONTENTS_TEAM2.	toolsplayerclip_teamone toolsplayerclip_teamtwo	(only in [confirm] )	Makes the brush only block a specific team. Unlike other compile parameters, this isn't a Boolean, but instead is an integer which is either 1 or 2.

Other

VMT flag	BSP flags assigned	Seen in VMT(s)	Availability	Description
%Compile2DSky	SURF_SKY SURF_SKY2D SURF_NOLIGHT removes SURF_BUMPLIGHT	toolsskybox2d		Makes the face render the 2D Skybox only, in addition to emitting light_environment light.
%CompileFog	none	ToolsFog	None	This may be a deprecated flag that so far has not been seen as being useful.
%CompileHint	SURF_NODRAW SURF_NOLIGHT SURF_HINT removes SURF_BUMPLIGHT	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 removes SURF_BUMPLIGHT	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. Not necessary for UnlitGeneric materials. Important:No effect in Hammer++ lighting preview. Important:Incompatible with %compileWater
%CompileNoShadows	SURF_NOSHADOWS		(only in ) (also in )	Prevents dynamic shadows from being cast onto the surface.
%CompileOrigin	CONTENTS_ORIGIN CONTENTS_DETAIL SURF_NODRAW SURF_NOLIGHT removes SURF_BUMPLIGHT	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 removes SURF_BUMPLIGHT	toolsskip		Removes the face during compilation, making the brush into sets of planes.
%CompileSky	SURF_SKY SURF_NOLIGHT removes SURF_BUMPLIGHT	toolsskybox		Makes the face render the (2D/3D) Skybox and emit light_environment light.
%CompileTrigger	SURF_NOLIGHT SURF_TRIGGER removes SURF_BUMPLIGHT	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, unless it has one of the exclusive flags above.
Every flag is available in all Source Engine branches, unless specifically mentioned in the Availability box

VMT flag	BSP flags assigned	Seen in VMT(s)	Availability	Description
%CompileBlockLOS	CONTENTS_BLOCKLOS	toolsblocklos		Makes the brush block only the line of sight for NPCs. Note:Also works for bots in .
%CompileDetail	CONTENTS_DETAIL			Forces the brush to no longer cut visleafs, similar to func_detail.
%CompileInvisible	CONTENTS_GRATE SURF_NODRAW SURF_NOLIGHT removes CONTENTS_SOLID removes SURF_BUMPLIGHT	toolsinvisible		Shortcut for %CompileNoDraw + %CompilePassBullets.
%CompileKeepLight	none			Tells the compiler to not set SURF_NOLIGHT when using -xbox VBSP parameter if %CompileWater is used. if the shader is set to Water(if before ) or UnlitGeneric.
%CompileLadder	CONTENTS_LADDER	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	SURF_NODRAW SURF_NOLIGHT removes SURF_BUMPLIGHT	toolsnodraw		Makes a brush behave like tools/toolsnodraw.
%CompileNonSolid	CONTENTS_OPAQUE removes CONTENTS_SOLID			Makes the brush not solid to anything. All faces of the brush must have %CompileNonSolid for the brush to be nonsolid. Bug: The material will be invisible if used on a brush with solid contents.  [todo tested in ?]
%CompilePassBullets	CONTENTS_GRATE removes CONTENTS_SOLID			Makes the brush behave like a grating, allowing bullets to pass through but blocking other objects. Useful for foliage or metal grates. Bug:Allows explosions through, but not bullets in .  [todo tested in ?] Bug:Non-functional in Counter-Strike: Global Offensive and Counter-Strike: Source.  [todo tested in ?]
%CompileTeam	CONTENTS_TEAM1 or CONTENTS_TEAM2	climb_versus	(in all games since )	Decides which team should be affected by this tool texture. Unlike other compile parameters, this isn't a Boolean, but instead is an integer which is either 1 or 2.
%CompileWater	CONTENTS_WATER SURF_WARP SURF_NOSHADOWS SURF_NODECALS removes CONTENTS_SOLID removes CONTENTS_DETAIL			Marks the brush as a water-type material. Makes it non-solid, allows swimming inside, etc.
%CompileWet	SURF_WET		(removed since )	[ Deprecated] Sets unused legacy Quake II flag (eventually replaced with SURF_NOPORTAL; deprecated in favor of surface properties.
%CompileSlime	CONTENTS_SLIME SURF_NODECALS removes CONTENTS_SOLID removes CONTENTS_DETAIL			same as %CompileWater, but with green splash particles. Bug: %CompileSlime uses default water splash particles.  [todo tested in ?]
%HotSurface	SURF_NOPORTAL		(in all games since )[confirm]
%NoPortal	SURF_NOPORTAL	toolsblack_noportal	(in all games since )	Makes the texture non-portalable unless Conversion Gel is used.
%NoPaint	SURF_NODECAL (aliased to SURF_NOPAINT)		(in all games since )	Makes the material unable to be painted by Gel. Implies $nodecal.
%CompileStairs	[confirm]	toolsstairs	(only in )	Makes brushwork traversable up to an angle of 63.4349488, as opposed to the usual 45°.

Other % parameters

A few other "shader parameters" start with %, but don't qualify as "compile flags".

Key	Parameter	Availability	Description
%tooltexture	texture		Used instead of $basetexture for: Texture thumbnails in Hammer Brush and displacement UV calculation in Hammer and in-game[confirm]
%notooltexture	boolean	(not in )	Used by Hammer to hide the material in the texture browser. Useful for textures that don't work correctly on brushes or displacements.
%keywords	string		Used to help filter textures in Hammer's texture browser. Comma-delineated.
%alphatexture	texture	(only in )	Used to cast texture shadows instead of $basetexture, even if $alphatest and/or $translucent are absent.