View source for L4D Level Design/Clip Brushes

{{L4D level intro menu}}

Looking around the tutorial_standards.vmf level in Hammer, you may have noticed that some of the brushes placed do not actually render in the game version of the level.

Similar to the trigger_changelevel brush that you created in the checkpoint tutorial, all trigger brush entities are invisible in the game.

There are also clip brushes that can block survivors and infected.

[[Image:l4d_hammer_clipbrush_01.jpg|thumb|left|500px|caption|Using a clip brush.]]{{clr}}

You can use these to cover geometry that players can get stuck on. The railings for the stairs in tutorial_standards.vmf are a good example of this.

To make a clip brush, simply create a brush and attach the tools/toolsclip texture to it.

[[Image:l4d_hammer_cliptexture_01.jpg|thumb|left|200px|caption|The tools/toolsclip texture.]]{{clr}}

Brushes with this texture applied to them will block all players, npc's, and physics objects. They will not block bullets.

You can also just block players by using the tools/toolsplayerclip texture.

[[Image:l4d_hammer_cliptexture_02.jpg|thumb|left|200px|caption|The tools/toolsplayerclip texture.]]{{clr}}

This is handy for above walls and fences that you want infected to climb over but you don't want players to accidentally get knocked over.

[[Image:l4d_hammer_clipbrush_02.jpg|thumb|left|500px|caption|Using a player clip brush.]]{{clr}}

The exterior area shown here from tutorial_standards.vmf is a good example of this.

== Nav Blockers ==

Sometimes, you may want to block the nav mesh without adding a clip brush. You might even want to block the nav for just survivor bots or just infected. You can use a brush entity called a <code>func_nav_blocker</code> to block the nav.

In the tutorial_standards map, a <code>func_nav_blocker</code> brush entity has been used to keep the survivor bots from trying to use the ladder nav before the ladder has been raised.

[[Image:l4d_hammer_nav_blocker_01.jpg|thumb|left|500px|caption|An example of a func_nav_blocker in the tutorial_standards map.]]{{clr}}

To create a <code>func_nav_blocker</code>:

# Use the '''Block Tool''' to create a brush along the area of the floor that you want to block the nav.
#: {{note|If you choose to rotate a brush at an angle between 0 and 90 degrees, the nav will be blocked along the bounding box of the func_nav_blocker.}}
# Apply the "tools/toolstrigger" texture to the brush.
# Use '''Tools > Tie to Entity''' to turn the brush into a brush entity and open the brush properties.
# Change the '''Class''' to "<code>func_nav_blocker</code>".
# Change the '''Name''' to something unique. In this case, I've used "ladder_nav_blocker".
# Change the '''Team(s) to block''' to "Survivor". If you want to block infected only, then change it to "Infected".

[[Image:l4d_hammer_nav_blocker_02.jpg|thumb|left|500px|caption|The func_nav_blocker properties.]]{{clr}}

You can also unblock the nav that a <code>func_nav_blocker</code> is blocking by sending an input to it.

[[Image:l4d_hammer_nav_blocker_03.jpg|thumb|left|500px|caption|The outputs tab to tell the func_nav_blocker to unblock.]]{{clr}}

Add an output with the following:
* '''My output named''': "OnFullyClosed" (This is set up for the ladder that gets raised.)
* '''Target entities named''': "ladder_nav_blocker"
* '''Via this input''': "UnblockNav"

{{NavBar|:L4D Level Design/Level Standards|L4D Level Design Basics Tutorial|L4D Level Design/Elevators}}

[[Category:Left 4 Dead]]
[[Category:Level Design]]