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
}

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

Name	Seen in .vmt	Availability	Effect
%CompileClip	toolsclip		Makes the brush block only players and NPCs. This is equivalent to a combination of %PlayerClip and %CompileNPCClip.
%CompileNPCClip	toolsnpcclip		Makes the brush block only NPCs. This implies NoLight and NoDraw. Template:ModernNote
%PlayerClip	toolsplayerclip		Makes the brush only block players.
%CompilePlayerControlClip	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	toolsgrenadeclip	(only in )	Makes the brush only block grenades.
%CompileDroneClip	toolsdroneclip	(only in )	Makes the brush only block drones.

Other

Name	Seen in .vmt	Availability	Effect
%Compile2DSky	toolsskybox2d		Makes the face render the 2D Skybox only, in addition to emitting light_environment light.
%CompileFog	ToolsFog		This may be a deprecated flag that so far has not been seen as being useful.
%CompileNoChop			Prevents "subdividing patches" on the surface. This presumably affects how the face is converted to triangles.
%CompileNoLight	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.
%CompileOrigin	toolsorigin		Deprecated:Sets the rotation origin of a brush entity. Leftover from ORIGIN in . Still functional in some branches (such as ), but is no longer necessary.
%CompileSkip	toolsskip		Removes the face during compilation, making the brush into sets of planes.
%CompileSky	toolsskybox		Makes the face render the (2D/3D) Skybox and emit light_environment light.
%CompileTrigger	toolstrigger		Makes the brush suitable for Triggers.

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. Template:ModernNote
%CompileDetail			Forces the brush to no longer cut visleafs, similar to func_detail.
%CompileHint	toolshint		Makes the face hint-cut visleafs. This implies NoLight and NoDraw.
%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 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. Template:ModernBug
%CompileNoShadows			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. Template:ModernNote
%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. Template:ModernBug
%NoPortal	toolsblack_noportal	(only in )	Makes the texture non-portalable unless Conversion Gel is used.
%NoPaint		(only in )	Makes the material unable to be painted by Gel.
%CompileStairs	toolsstairs	(only in )	Makes brushwork traversable up to an angle of 63.4349488, as opposed to the usual 45°.