System materials with a special behavior. Used widely on all maps.

	common/caulk A system material designed to 'caulk' or seal a map. In-game, it is a transparent solid texture. It is best applied to all surfaces which a player will be unable to see while in-game. This texture generate no draw surfaces.
	common/clip Invisible material which clips movement of players. Do not affects footsteps (footstep tracing skips clipsurfaces to get real material player standing on).
	common/monsterclip Clip only NPC movement.
	common/fullclip PlayerClip + MonsterClip.
	common/origin Normally brush entities have no origin. Center of brush covered by this textures will set origin of it's parent BModel. This origin is used for movement (path spots) and rotation.
	common/black Black wall, hides any stuff behing it. Dont cast a shadow.
	common/areadisable Black wall on steroids, this also hides any transparent entities, marks, effects.
	common/ilava Invisible, sets brush contents to water. Also used on covering junction sides of water brushes (when making a long river). Water damage the player at slight rate.
	common/islime Invisible, sets brush contents to swamp. Swamp slows down player and damage at slight rate when he moves.
	common/ilava Invisible, sets brush contents to lava. Also used on covering junction sides of lava brushes. Lava damages player at hight rate (even in mist form), almost impossible to walk.
	common/lightgrid World brush with this texture will make boundaries of entity static lighting. There is no other use.

Rarely used materials

This system materials used to create very special things.

	common/blackshadow Black wall but casts shadows from static lights.
	common/lightblock Invisible surface that blocks lighting.
	common/lighthull Same as lightblock but blocks lighting from inside.
	'common/hint This brush splits visibility data making more portals. Rarely used to enhance portal culling.
	common/nodraw Caulk that doesnt block visibility data.
	common/dpshadow Invisible wall that cast realtime shadows. Weird.
	dpbihclip This invisible texture is inaccessible from texture window. It is ised on collision meshes to define BIH support with no reatime shadows.
	dpbihplayerclip BIH support + playerclip.
	dpbihclipandshadow BIH support + cast realtime shadows.
	collision This texture should be used with "collision" mesh only used by ODE.

Markers

This materials dont have any effects. Thay are just used to separate things.

	common/trigger All triggers should be marked with this material.
	common/roof Material to cover invisible rooftops on func_roof.
	common/mark1 ... common/mark9 Visible materials to mark various stuff, like light glares, zones.

This materials are there, but have no functionality.