View source for Nav Mesh Editing

{{LanguageBar|title = Navigation Mesh Editing}}

{{back|Nav Mesh}}
This page is about creating and editing the [[NAV]] file for a map in-game.

For a list of commands, see [[Navigation Mesh Commands]].

== Limitations ==
{{Warning|There is no "undo" command in the Navigation Mesh editing system. The only thing one can do is reload the map without saving.}}
{{Tip|'''Save your work''' often via the <tt>nav_save</tt> command in case the game crashes. If you use binds for editing, e.g. for <tt>nav_mark</tt>, you can bind <tt>nav_save</tt> along with it: {{code|bind <key> "nav_save; nav_mark"}}.}}
{{Warning|The game may crash while editing the nav mesh, especially after [[#Delete|deleting]], [[#Split|splitting]] and [[#Merge|merging]] areas, ...
* ...if bots are active. To prevent this, execute <tt>bot_kick</tt> before editing and reload the map before adding bots. You may want to <tt>nav_analyze</tt> anyway, which also reloads the map.
* ...if {{ent|func_nav_blocker}} entities receive <tt>BlockNav</tt> or <tt>UnblockNav</tt> inputs.
}}

== Automatic Navigation Mesh Generation ==
A new navigation mesh <tt><game>/maps/<mapname>[[.nav]]</tt> for a map can be generated by using the '''<tt>[[Navigation_Mesh_Commands#Mesh_generation|nav_generate]]</tt>''' command while the map is loaded which requires {{ent|sv_cheats|1}}. Depending on the size and complexity of the map, this may take a few minutes to a few hours, but mostly about 5 minutes. Large forests are an example for structures that may take a long time to compute a .nav for. In this case you may want to create the navigation mesh manually and with less precision, i.e. without carving out every tree. This could also be achieved by compiling a map with less detail, generating the nav mesh and keeping it for the original map.

You can then upload the created .nav file to your server.

It is recommended that map creators create navigation meshes before releasing their map to the public.

{{Note|{{css}}{{csgo}} If [[bot]]s are added on a map with no .nav file, the game will <tt>nav_generate</tt> automatically. This affects custom maps particularly.
If the .nav generation takes too long, this automatic process can be avoided by making sure that bots will not join the game e.g. by invoking {{ent|bot_kick}} before choosing a team.}}

=== What is computed during generation ===
The following steps occur during Navigation Mesh generation:
* Starting at a player spawn point, walkable space is sampled by "flood-filling" outwards from that spot, searching for adjacent walkable points
* Rectangular ''Navigation Areas'' are constructed from the sampled data
* Hiding and Sniper spots are computed
* Encounter Spots and Approach Points are computed (this can take awhile)
* Initial Encounter areas are computed

=== Viewing the Navigation Mesh ===
To see the current navigation mesh, type <tt>nav_edit 1</tt>. To turn the mesh editor off, type <tt>nav_edit 0</tt>. You will need to have {{ent|sv_cheats|1}} to be able to view the navigation mesh.

=== Explicitly marking walkable areas (i.e: "There's no mesh upstairs") ===
Some maps that have very steep stairs, ramps, or hills may confuse the generation system, resulting in the Navigation Mesh not covering the entire map.  To solve this, you can manually place additional ''walkable markers'' that tell the generator to search outwards from that point during its sampling phase.

To add one or more walkable markers, first aim your view towards a known walkable spot in your map, then type <tt>[[Navigation_Mesh_Commands#Mesh_generation|nav_mark_walkable]]</tt> in the console. When you are finished placing markers, type <tt>[[Navigation_Mesh_Commands#Mesh_generation|nav_generate_incremental]]</tt> (followed by <tt>nav_clear_selected_set</tt>) or <tt>nav_generate</tt> to re-generate the mesh.

You can remove all previously placed walkable markers using the <tt>nav_clear_walkable_marks</tt> command.

=== Quickly generating meshes for testing===
The analysis phase of the generator can be quite time consuming.  To skip it, type <tt>nav_quicksave 1</tt> in the console.  
:{{note|"Quicksaving" skips the analysis phase, and the resultant nav mesh will be missing important data required by the CS Bots and Hostages higher-level planning and attention systems.  While useful for testing, editing, and tuning a nav mesh, be sure to do a full analyze (ie: <tt>nav_analyze</tt> with <tt>nav_quicksave 0</tt>) before publishing your nav file to others.}}

== Editing the Navigation Mesh ==
[[File:nav_edit.jpg|thumb|300px|right|Enabling the Navigation Mesh editor in de_dust]]
The automated Navigation Mesh generator does a reasonable job of constructing a mesh, allowing you to start using Bots and Hostages on custom maps easily.

However, careful hand-tuning of the Navigation Mesh can noticeably improve the performance of Bots. In addition, manually decorating the mesh with ''Place names'' allows the Bots to tell others where events occur, enhances the Counter-Strike radar and includes Place names in all radio messages.

To enable the editor, type <tt>nav_edit 1</tt> in the console (type <tt>nav_edit 0</tt> to disable it).

* The white cross in the center of your view is the ''cursor''.
* The navigation area you are pointing at is the ''selected area'' or ''highlighted area'' and is shown with a <span style=color:yellow>yellow</span> outline.
* Navigation areas that can be reached from the selected area are shown in <span style=color:red>red</span>.
* The white line in the selected area denotes where the area will be [[#Split|split]] if the <tt>nav_split</tt> command is executed.
* Exactly one area can be ''marked'' (or unmarked) by pointing at it and invoking <tt>nav_mark</tt> and is shown with a <span style=color:cyan>cyan</span> outline. This is used for many other commands that need two operands, being the ''marked'' and the ''selected'' area.
* Areas that are part of the current ''[[#Selected Sets|selected set]]'' have a <span style=color:white>white</span> tint. To clear any selection, invoke {{ent|nav_clear_selected_set}}.

=== Creating a new area ===
This can be done with the commands <tt>nav_begin_area</tt> and <tt>nav_end_area</tt>.
{|
| [[File:nav_begin_area.jpg|300px|thumb|left|Place your cursor at where a corner of the new area should be and execute <tt>nav_begin_area</tt>.]]
| [[File:nav_drag_area.jpg|300px|thumb|left|Move your cursor to drag out the area's extent.]]
| [[File:nav_end_area.jpg|300px|thumb|left|Place your cursor at where the opposite corner of the new area should be and execute <tt>nav_end_area</tt>.]]
|}
{{Note|Areas created like this have no connection to the existing nav mesh by default. It will bidirectionally connect to a ''marked'' area upon <tt>nav_end_area</tt> being executed.}}
{{Tip|Use <tt>nav_snap_to_grid 1</tt> to get consistent rectangle sizes.}}
{{Tip|The 4 corners of the resulting area will be on the same height. If the ground is not even, begin new areas with the highest corner to prevent it from being created under the floor. A floating area can easily be shifted down to the ground using <tt>nav_corner_place_on_ground</tt> while aiming at it.}}
{{Tip|Instead of creating a lot of small areas, one could instead create one huge area, if possible, and [[#Split|nav_split]] it down to the needs. Since connections are created with every split, no connection must be created manually using <tt>nav_connect</tt>. Redundant areas can be deleted.}}

=== Delete ===
To delete an area, aim your cursor at it so that it is highlighted and execute <tt>nav_delete</tt>. Alternatively you can mark an area or select a set of areas to delete multiple areas.
{{tip|[[#Delete|Deletion]], [[#Split|splitting]] and [[#Merge|merging]] can be useful for playing certain parts of the map.}}

=== Connect two areas ===
{| style="float:right;"
| [[File:nav_jump_down.jpg|300px|thumb|right|'''<span style="color: rgb(80, 80, 255);">One-way connections</span>''' (marked with dark blue lines) are usually used for "jump-down" links from a ledge to the ground.]]
| [[File:nav_connections.jpg|300px|thumb|right|'''<span style="color: rgb(51, 204, 204);">Bidirectional (two-way) connections</span>''' (marked with light blue lines at the area edges) allow bots to freely move between the two areas.]]
|}
The connections between areas define whether one can move from one area to another.

Usually these connections are ''bidirectional'', meaning one can move back and forth between two areas at will.
However, sometimes the connection is ''one way'', as in the case of ledges that can be jumped down, but not back up.
One-way links can also be useful for forcing bots to travel a specific direction, perhaps to set up for a tricky jump.

To make a '''<span style="color: rgb(80, 80, 255);">one-way connection</span>''' from area A to area B (meaning you can move from A to B):
# Mark area A: Place your cursor on it and execute <tt>nav_mark</tt>.
# Aim at area B and execute <tt>nav_connect</tt>.

To make a '''<span style="color: rgb(51, 204, 204);">bidirectional connection</span>''', repeat the above steps reversing the roles of A and B.
{{tip|In a selected set, <tt>nav_connect</tt> will try to bidirectionally connect the first selected area and every subsequently selected area. Use <tt>nav_connect</tt> and selected sets to quickly make bidirectional connections.}}

=== Disconnect two areas ===
To remove '''all''' connections between the areas A and B:
# Mark area A: Place your cursor on it and execute <tt>nav_mark</tt>.
# Aim at area B and execute <tt>nav_disconnect</tt>.
{{tip|When ran with a selected set, <tt>nav_disconnect</tt> will try to remove connections between the first selected area and every subsequently selected area.}}
{{tip|Use <tt>nav_disconnect_outgoing_oneways</tt> to quickly disconnect all one-way connections. This command also works in a selected set.}}
{{clr}}

=== Split ===
Splitting divides an area into two bidirectionally connected areas.
{{tip|[[#Delete|Deletion]], [[#Split|splitting]] and [[#Merge|merging]] can be useful for playing certain parts of the map.}}
{|
| [[File:nav_edit.jpg|300px|thumb|left|Position yourself and the cursor so that the white split line is where you want the area to be split.]]
| [[File:nav_split.jpg|300px|thumb|left|Execute <tt>nav_split</tt> to get two adjacent, inter-connected areas.]]
|}

=== Merge ===
Merging two areas reduces the area count.
{{tip|[[#Delete|Deletion]], [[#Split|splitting]] and [[#Merge|merging]] can be useful for playing certain parts of the map.}}

Both areas must be the same size along the edge to be merged. It is not required that the two areas are adjacent.

The resulting area will retain all of the connections of the original two areas, and inherit properties (i.e: Place names, etc) from the marked area.
{{Tip | While moving from point A to point B, bots tend to prefer routes with less areas to travel through, so a route can in theory be made more attractive to bots by merging some areas.}}
{|
| [[File:nav_mark.jpg|300px|thumb|left|Aim your cursor at the first area and execute <tt>nav_mark</tt>.]]
| [[File:nav_pre_merge.jpg|300px|thumb|left|Aim at second area.]]
| [[File:nav_post_merge.jpg|300px|thumb|left|Execute <tt>nav_merge</tt>.]]
|}

=== Splice ===
Splicing creates a new area between two existing areas. Splicing is a powerful tool, and can be used to easily create sloped areas, as shown in the example below.
{{Tip | It is '''not''' required that the two areas have the same width. The width of the resulting area will be the smaller of the two.}}
{|
| [[File:nav_prep_splice.jpg|300px|thumb|left|Aim your cursor at the first area and execute <tt>nav_mark</tt>.]]
| [[File:nav_pre_splice.jpg|300px|thumb|left|Aim your cursor at the second area.]]
| [[File:nav_post_splice.jpg|300px|thumb|left|Execute <tt>nav_splice</tt>.]]
|}

=== Selected Sets ===

While {{ent|nav_mark}} allows you to mark at most one area, ''Selected Sets'' allow you to select multiple areas and operate on them. Adding or removing areas to the selected set does not manipulate them in the first place.
The advantage of using selected sets is that it makes it a lot easier to do the same operation on multiple areas at once such as marking them with area attributes or moving them, see [[#Moving|below]].
{{note|[[#Ladders|Ladders]] cannot be added to a selected set.}}
There are multiple ways to add and remove areas to the selected set:
* '''To clear any selection''', invoke {{ent|nav_clear_selected_set}}.
* '''To add or remove single areas from the selected set''', point at an area and invoke {{code|nav_add_to_selected_set}} or {{code|nav_remove_from_selected_set}}. If any selected set exists, {{code|nav_mark}} toggles the selected state of the area that is pointed at.
* '''To add or remove areas by looking at them''', point at an area and invoke {{code|nav_begin_selecting}}. From now on until {{ent|nav_end_selecting}} is invoked, every (!) area that the player points at is added to the selected set.<br>The commands {{ent|nav_begin_deselecting}} and {{ent|nav_end_deselecting}} work analogously except that areas are removed from the selected set.
* '''To select connected areas''', point at an area and invoke {{code|nav_flood_select}} to add the area that was pointed at to the selected set as well as all areas that can be reached from it in terms of outgoing '''and''' ingoing connections. This means that if there is a path from area A to area B then flood selecting at A yields the '''same''' result as flood selecting at B even though the path from A to B might be one-way.
* '''To add areas in a sphere around yourself''', position yourself appropriately and invoke {{ent|nav_select_radius|<distance>}} to add all areas to the selected set that are at most <tt><distance></tt> units away from yourself. After the invokation, the game prints the number of areas that have been added to the selected set. Passing a negative distance behaves like passing a positive one.
:{{Tip|To select the entire nav mesh, you can use {{code|nav_select_radius 999999}}. Note that {{code|nav_flood_select}} doesn't necessarily select the entire nav mesh but you can compare the number of areas that these two commands add to an empty set - if the numbers are equal you know that the nav mesh contains no orphaned areas.}}
* '''To select areas using a rectangle''', invoke {{ent|nav_begin_drag_selecting}} at one corner of it. From now on, the game shows a quboid with a fixed height of 32 units between the point that the player looked at when the previous command was executed and the current point that the player looks at. All areas that touch this quboid are drawn with a <span style=color:green>green</span> tint. All green areas are added to the selected set when {{ent|nav_end_drag_selecting}} is invoked.<br>The commands {{ent|nav_begin_drag_deselecting}} and {{ent|nav_end_drag_deselecting}} work analogously but with a <span style=color:red>red</span> tint.
{|
| [[File:css_nav_begin_drag_selecting_01.jpg|300px|thumb|left|Before executing <tt>nav_begin_drag_selecting</tt>.]]
| [[File:css_nav_end_drag_selecting_01.jpg|300px|thumb|left|Before executing <tt>nav_end_drag_selecting</tt>.]]
| [[File:css_nav_begin_drag_deselecting_01.jpg|300px|thumb|left|Before executing <tt>nav_begin_drag_deselecting</tt>.]]
| [[File:css_nav_end_drag_deselecting_01.jpg|300px|thumb|left|Before executing <tt>nav_end_drag_deselecting</tt>.]]
|}

=== Moving ===

The areas of a selected set can be shifted with the mouse pointer by invoking {{ent|nav_begin_shift_xy}} and {{ent|nav_end_shift_xy}}.<br>
To shift them by exact coordinates, use {{ent|nav_shift|<x> <y> <z>}}.

{{Tip|If you have moved your entire map in the editor but you had already worked on the nav mesh, you can move the entire nav mesh by the same amount by selecting all of it using {{ent|nav_select_radius|999999}} and shift it (multiple times) using {{ent|nav_shift|<x> <y> <z>}}. When done, use {{ent|nav_clear_selected_set}} to clear the selection and {{ent|nav_analyze}} the mesh because otherwise hiding spots etc. are not shifted.}}

=== Area Attributes ===
[[File:nav_jump.jpg|300px|thumb|A jump area and a no_jump area.]]
[[File:nav_crouch.jpg|300px|thumb|Crouch areas.]]
Area attributes influence the behavior of bots to act in specific ways. Each area can have any combination of attributes. Most area attributes are required to be set manually, but a portion of attributes are set automatically and cannot be set manually.

{{note|Games may implement their own set of area attributes, or in a few cases, implement attributes through a different system which is the case in {{l4d|4}}, {{l4d2|4}} and {{tf2|4}}. So even though the following base attributes exist in all games that support navigation meshes, the AI may not take them into account. In the aforementioned games, ''only'' the '''precise''' area attribute is considered.}}

==== Base attributes ====
These are the attributes that exist since {{css|4}}.
* To set or to clear an attribute from the highlighted area or all areas of a selected set, invoke {{code|nav_mark_attribute <ATTRIBUTE>}} or {{code|nav_clear_attribute <ATTRIBUTE>}}. The game will list all available attributes in the console while typing.
* To toggle an attribute for an area, aim at it and execute the corresponding command, e.g. {{code|nav_jump}}.

{| class=wikitable
! Attribute !! Value !! Toggle Command !! Mark !! Effect
|-
| <tt>CROUCH</tt> || 1 || {{code|nav_crouch}} || <span style=color:#88f>blue diagonal</span> || Forces bots to crouch when moving through this area.
|-
| <tt>JUMP</tt> || 2 || {{code|nav_jump}} || <span style=color:#0f0>green X</span> || Tells bots to jump in order to reach the higher connected area and that this area is not usable as a hiding/sniping spot.
|-
| <tt>PRECISE</tt> || 4 || {{code|nav_precise}} || <span style=color:#0f0>green +</span> || Prevents bots from skipping this area and stops bots from avoiding obstacles. The precise attribute can help in places where bots can easily fall off, like catwalks with no railing, or when setting up specific routes for a jump.
|-
| <tt>NO_JUMP</tt> || 8 || {{code|nav_no_jump}}|| <span style=color:red>red rhombus ♢</span> || Forces bots not to jump. This is useful to prevent excessive jumping. However, bots can get stuck if jumping is required to keep going.<br>{{csgo}} This attribute will not prevent an explicit <tt>action_jump</tt> in [[CS:GO Bot Behavior Trees|behavior trees]].
|-
| <tt>STOP</tt> || 16 || {{code|nav_stop}} || <span style=color:red>red octagon</span> || Tells bots to stand still for a short moment when entering this area. Useful to slow bots down to line up tricky jumps more accurately.
|-
| <tt>RUN</tt> || 32 || {{code|nav_run}} || <span style=color:#88f>two blue arrows</span> || Tells bots explicitly to run in this area.
|-
| <tt>WALK</tt> || 64 || {{code|nav_walk}} || <span style=color:#0f0>one green arrow</span> || Tells bots explicitly to walk silently in this area.
|-
| <tt>AVOID</tt> || 128 || {{code|nav_avoid}} || <span style=color:red>two red triangles</span> || Tells bots not to use the area unless the normal route has become too dangerous. {{only|{{css}}{{csgo}}}}
|-
| <tt>TRANSIENT</tt> || 256 || {{code|nav_transient}}  || <span style="border:1px dashed white; padding:0.25em; white-space:nowrap">dashed outline</span> || {{todo|Effect? Description from {{css}}: Toggles the 'area is transient and may become blocked' flag used by the AI system.}}
|-
| <tt>DONT_HIDE</tt> || 512 || {{code|nav_dont_hide}} || - || Tells bots not to use this area as a hiding spot.
|-
| <tt>STAND</tt> || 1024 || {{code|nav_stand}} || - || Tells bots not to crouch while hiding in this area. {{idea|{{css}}{{csgo}} If you want bots to crouch only in specific places, apply this to the whole mesh and remove it where needed.}}
|-
| <tt>NO_HOSTAGES</tt> || 2048 || {{code|nav_no_hostages}} || - || Tells [[hostage_entity|hostage]] [[NPC]]s not to use this area. Only effective in {{css}}.
|-
| <tt>STAIRS</tt> || 4096 || - || <span style=color:#0f0>green lines</span> ||
|-
| <tt>NO_MERGE</tt> || 8192 || - || - ||
|-
| <tt>OBSTACLE_TOP</tt> || 16384 || - || - ||
|-
| <tt>CLIFF</tt> || 32768 || - || - ||
|-
| ''Blocked'' || ? || - || <span style="color:cyan; border:1px solid cyan; padding:0.25em; white-space:nowrap">cyan rectangle</span> || Tells bots not to use this area. This attribute is only set automatically by the game. Example cases include:
* Blocking {{ent|func_nav_blocker}} entities {{l4d|since}}
* {{l4ds}} Closed {{ent|func_door}} entities
* {{tf2}} Spawn room exit doors
* {{csgo}} Locked {{ent|prop_door_rotating}} entities.
Furthermore, there are the related console commands <tt>nav_debug_blocked, nav_update_blocked, nav_check_floor, nav_select_blocked_areas</tt>.
|-
| ''Damaging'' || ? || - || <span style="color:#88f; border:1px solid #88f; padding:0.25em; white-space:nowrap">blue rectangle</span> || Tells bots not to use this area. This attribute is only set automatically by the game. Example cases include:
* Enabled {{ent|trigger_hurt}} entities.
* {{csgo}} Fire caused by {{ent|weapon_molotov}} or {{ent|weapon_incgrenade}}.
Furthermore, there are the related console commands <tt>nav_debug_blocked, nav_update_blocked, nav_check_floor, nav_select_blocked_areas</tt>.
|}

==== Left 4 Dead 1&2 ====
{{main|List of L4D Series Nav Mesh Attributes}}

In {{l4d|4}} and {{l4d2|4}}, an alternate set of area attributes named "Spawn Attributes" is available with a very different implementation. Spawn Attributes are identified not by shapes but color, and their attribute names use the color white rather than yellow. The attributes's roles are also different, commonly assisting the "Director" over player AI decision-making.

<tt>z_debug 1</tt> is required to view Spawn Attributes. 

==== Team Fortress 2 ====
{{main|List of TF2 Nav Mesh Attributes}}

{{tf2|4}} has fittingly named "TF attributes", a simpler implementation of "Spawn Attributes" from {{l4d|4}} and {{l4d2|4}} which tends to assist the game logic in a general sense, such as blocking nav areas when a capture point is captured. These attributes can be set and cleared via the command <tt>tf_mark</tt>. Use <tt>tf_show_mesh_decoration 1</tt> to display all TF attributes at once, coloring all nav areas with a specific color even if not hovered over. {{bug|Multiple TF attributes in one nav area will display overlapping text.}}

{{note|Areas can be blocked for only specific teams in {{tf2}} in different ways (which can cause confusion). Use the <tt>tf_show_blocked_areas</tt> to get the full context.}}

{{note|Some TF attributes, such as the <tt>TF_NAV_WITH_X_POINT</tt>, <tt>TF_NAV_BLOCKED_UNTIL_POINT_CAPTURE</tt> and <tt>TF_NAV_BLOCKED_AFTER_POINT_CAPTURE</tt> are processed by exclusion; only one of the TF attributes in such groups will be processed. {{workaround|One can distribute these attributes across a specific chain of nav areas to allow for flexible TF attribute logic. 

Described as: Source Nav Area <-> Conditional Nav Area 1 (with TF attributes exclusionary to Conditional Nav Area 2) <-> Conditional Nav Area 2 (with TF attributes exclusionary to Conditional Nav Area 1) <-> Target Nav Area}}}}

{|class="standard-table mw-collapsible"
!  !! (Exclusionary) processing order
|-
!TF_NAV_WITH_<Nth>_POINT
|
# TF_NAV_WITH_SECOND_POINT
# TF_NAV_WITH_THIRD_POINT
# TF_NAV_WITH_FOURTH_POINT
# TF_NAV_WITH_FIFTH_POINT
|-
!TF_NAV_BLOCKED_<X>_POINT_CAPTURE
|
# TF_NAV_BLOCKED_UNTIL_POINT_CAPTURE
# TF_NAV_BLOCKED_AFTER_POINT_CAPTURE
|}

{{note|Using the <tt>TF_NAV_BLOCKED_[UNTIL/AFTER]_POINT_CAPTURE</tt> attribute will implicitly mean "Blocked until/after the ''first'' point is captured", which is why there is no <tt>TF_NAV_WITH_FIRST_POINT</tt> attribute.}}

==Testing the Nav Mesh==

After changing the nav mesh, use {{ent|nav_analyze}} to generate data used by bots. It will reload the map upon completion.
{{note|Encounter spots and encounter paths generated by {{ent|nav_analyze}} without {{ent|nav_quicksave|1}} are not used in {{tf2|4}}.}}

{{ent|bot_moveto}}, to direct puppet bots to move to a particular point.

{{bug|{{ent|bot_moveto}} only works for puppet bots. {{workaround|TF2 bots will go to {{ent|item_teamflag}} in many game modes. This mechanic can be exploited to move NextBot bots to a particular nav mesh.{{only|{{tf2}}}} {{CodeBlock|alias move_red_tf_bot_to_cursor "ent_remove red_bots_go_here; ent_create item_teamflag teamnum 3 targetname red_bots_go_here OnPickup !self,ForceReset,0,-1"
alias move_blu_tf_bot_to_cursor "ent_remove blu_bots_go_here; ent_create item_teamflag teamnum 2 targetname blu_bots_go_here OnPickup !self,ForceReset,0,-1"}} }}}}

== Place names (callouts) ==
Once a nav mesh is generated, '''Place names''' can be assigned to nav areas to label regions of the map. For instance, if there is a prominent house in the map, all of the nav areas in the house can be tagged with the <tt>House</tt> place name.

Place names have multiple uses:
* In the top left of the screen, each player sees his current place, which is the place name of the closest nav area.
* The chat displays the place of players using a radio command. This is also the case when they throw grenades. Example:
*:<tt>ChicagoTed @ '''Apartment''' (RADIO): Fire in the hole!</tt>
* {{css}} Bots use them to announce from where they are reporting in.
* {{csgo}} When using the ping tool, the place name is shown with it.
{{warning|{{csgo}} If the closest nav area to the center of a [[func_bomb_target]] has any place name, then the bomb target will be bombsite '''A''' if that place name is <tt>Bombsite</tt> or <tt>BombsiteA</tt>, otherwise it will be bombsite '''B'''. If you don't pay attention, two bombsites can get the same labeling, causing the radar to show just one!}}

=== Adding Place names ===
{| class=standard-table style=float:right
|+ Place name Editor
! Nav Area Color !! Nav Area...
|-
!style=color:#f00| red
| has no place name
|-
!style=color:#0f0| green
| has the current place name
|-
!style=color:#00f| blue
| has a place name, but not the current
|}

To add or change the name of a location, you need to turn on the place name editor. Make sure <tt>nav_edit</tt> is set to 1, then type
:<tt>nav_toggle_place_mode</tt>.
When the place name editor is enabled for the first time, all nav areas should turn red. To select a place name that should be assigned to some areas, type
:<tt>nav_use_place <place name></tt>,
for example <tt>nav_use_place Bedroom</tt>.

For a list of all available place names, execute <tt>nav_use_place</tt> with no argument.

Next, aim your cursor at an area you want to label with that place name and toggle the ''Place Painting Mode'' by executing 
:<tt>nav_toggle_place_painting</tt>.
Look around carefully! While ''Place Painting'' is active, each area that you point at with your crosshair will be tagged with the current place name that you selected and turn green in color. To stop painting, invoke the same command again.

You can change the place name you are painting with by typing <tt>nav_use_place <new place name></tt>. Notice that after changing the place name, all areas that are already painted with a different name will turn blue and areas painted with the name you just changed to will turn green.
{{tip|
* To select the place name that is assigned to a specific nav area, point at it and invoke <tt>nav_place_pick</tt>.
*[[Bind]] <tt>nav_toggle_place_painting</tt> and/or <tt>nav_place_pick</tt> to mouse buttons.
}}
When you are finished editing place names, exit the place mode with <tt>nav_toggle_place_mode</tt>.

There are several additional commands that provide tools for picking, flood-filling, replacing, and so on. For a complete reference, see [[Nav Mesh Commands#Place name commands|Place name Commands]].

;See also:
: {{css}} [[Standard Place Names for CS:S]]
: {{csgo}} [[Standard Place Names for CS:GO]].

== Common mesh problems and solutions ==
=== Extraneous areas on stairs and ramps ===
The automatic generation system tends to build areas that hang off the side of stairs and ramps.  These should be removed to force the bots to take the stairs or ramp straight-on.

=== Railings ===
Railings can be a problem for the current bot navigation system, this includes jump-down links that must pass over railings, they should be avoided unless necessary.  The bots will eventually make these jumps, but they are not terribly elegant while doing so.

=== Preventing excessive jumping ===
Use the <tt>nav_no_jump</tt> command to flag the area to disable jumping. {{only|text=en|{{css}}{{csgo}}}}

=== Dealing with rotating doors ===
Clip off the nav area to leave an empty space in the nav mesh to allow for the rotating door. You may have to remake the nav square if deleting part of an existing one doesn't work.

Bots will sometimes try to walk through the opened door brush from one nav area to another and get stuck. Either removing the adjacent nav area or configuring the areas and connections so the bots have to walk around the opened door should prevent this.

== Advanced editing techniques ==
=== Ladders ===
For ladders, there is a slightly different type of nav area that must be built manually on ''climbable surfaces''. Your editing cursor will turn green when pointing at one. But once created, nav areas on ladders behave the same as every other nav area in terms of selecting and connecting.

;Creation using {{ent|nav_build_ladder}}
{|
| [[File:nav_build_ladder_before.jpg|300px|thumb|left|Point at a climbable surface. Note the green cursor.]]
| [[File:nav_build_ladder_after.jpg|300px|thumb|left|Execute <tt>nav_build_ladder</tt>. The game might also create connections at the top and bottom.]]
|}

;Creation using {{ent|nav_begin_area}} and {{ent|nav_end_area}}
If <tt>nav_build_ladder</tt> isn't what you need, you can manually create a ladder. This can be useful to get bots to start going up the ladder, and jump off halfway up, onto the crate:
{|
| [[File:nav_begin_ladder.jpg|300px|thumb|left|Aim at the first corner and execute <tt>nav_begin_area</tt>.]]
| [[File:nav_drag_ladder.jpg|300px|thumb|left|Move your cursor to drag out the ladder's extent.]]
| [[File:nav_end_ladder.jpg|300px|thumb|left|Execute <tt>nav_end_area</tt>.]]
|}

;Reversing Ladders
Sometimes a ladder will be created facing the wrong way and show up red. The ladder is drawn in green if it is facing you. To change its orientation, simply point at it and use <tt>nav_ladder_flip</tt>.
{|
| [[File:nav_ladder_backward.jpg|300px|thumb|left|Ladder facing into the wall (incorrect)]]
| [[File:nav_ladder_forward.jpg|300px|thumb|left|Ladder facing away from the wall (correct)]]
|}

=== Obstacle avoidance and precision movement ===
Use <tt>nav_precise</tt>, <tt>nav_walk</tt>, and <tt>nav_stop</tt> to disable local obstacle avoidance behaviors and control bot movement.

The <tt>WALK</tt> and <tt>STOP</tt> attributes are only used in {{css|4}} and {{csgo|4}}.

=== Controlling where bots can hide ===
Use {{ent|nav_dont_hide}} or {{ent|nav_mark_attribute|DONT_HIDE}} to prevent bots from hiding in certain areas.
This can be used to force the creation of hiding spots during the analysis phase.

=== Setting up sniper spots ===
Mark an area using <tt>nav_walk</tt> and execute {{ent|nav_make_sniper_spots}}. This will break the area into small sub-areas which are used internally by the navigation mesh to encourage sniping.

{{warning|{{only|{{tf2|4}}}} Hiding spots only determine where TFBot Spies lurk; Sniper spots can be marked with {{ent|func_tfbot_hint}}, but they are only used by Snipers in [https://wiki.teamfortress.com/wiki/Mann_vs._Machine Mann vs. Machine]; otherwise the game uses theater and vantage points as sniper spot replacements.}}

[[File:MaximumJumpCrouch.jpg|300px|thumb|right|Highest possible crouchjump]]

=== Lining up tricky jumps and narrow doorways ===
Arranging nav areas to force specific paths.

* If the bots are getting hung up on the sides of a door or window, you can carve out a narrow path through the middle of the opening.
* The highest a bot will try to jump is 58 units.  If the top of a jump is 59 or more units above the bottom, bots will give up as soon as they jump. If this happens in a spot that the bots can actually jump up to, use {{ent|nav_corner_lower}} to lower the upper nav area slightly.

=== Aerial movement ===

Bots will attempt to move on a nav area ''regardless if they are on the ground.'' This mechanism can be exploited by utilizing nav areas in the air to produce aerial movement in bots. For example, areas can be manipulated to produce an L-shaped path where the middle area (preferably marked with PRECISE) is low enough for the bot to "touch" the area and move on it. When touching the area, the bot will turn to go to the next area, hence the bot performing to air strafes. 

{{todo|Illustrate the layout of a typical area layout for an airstrafe. Areas are aranged in an L-shape and then connected in air.}}
{{note|The bot will be moving forward, when hitting the turning area.}}

== Import and Export areas ==
{| style="background:transparent; float:right; margin-left:2em"
|- style=vertical-align:top
|
File format:
<source lang=cpp>
"Selected Nav Areas"
{
	"version" "1"
	
	"<NavAreaID>" <NavArea>
	"<NavAreaID>" <NavArea>
	"<NavAreaID>" <NavArea>
	// ...
}


// <NavAreaID> is an integer.
// <NavArea>:
{
	// corner coordinates:
	"NorthWest" <Vector>
	"NorthEast" <Vector>
	"SouthWest" <Vector>
	"SouthEast" <Vector>
	
	// connections, all four optional:
	"North" <Connections>
	"East"  <Connections>
	"South" <Connections>
	"West"  <Connections>
	
	"Place"      "<string>"
	"Attributes" "<integer>"
}

// <Vector>:
{
	"x" "<float>"
	"y" "<float>"
	"z" "<float>"
}

// <Connections>:
{
	"0" "<NavAreaID>"
	"1" "<NavAreaID>"
	"2" "<NavAreaID>"
	// ...
}
</source>
|
Example:
<source lang=cpp>
"Selected Nav Areas"
{
	"version"		"1"
	"4640"
	{
		"NorthWest"
		{
			"x"		"-850.000000"
			"y"		"1225.000000"
			"z"		"-0.164574"
		}
		"NorthEast"
		{
			"x"		"-725.000000"
			"y"		"1225.000000"
			"z"		"-5.690256"
		}
		"SouthWest"
		{
			"x"		"-850.000000"
			"y"		"1450.000000"
			"z"		"-4.490265"
		}
		"SouthEast"
		{
			"x"		"-725.000000"
			"y"		"1450.000000"
			"z"		"-3.990265"
		}
		"North"
		{
			"0"		"4765"
			"1"		"4780"
		}
		"East"
		{
			"0"		"4641"
		}
		"West"
		{
			"0"		"4431"
			"1"		"4432"
		}
		"Place"		"OutsideLong"
		"Attributes"		"1032"
	}
}
</source>
|}
Nav areas can be imported and exported through {{ent|nav_save_selected}} and {{ent|nav_merge_mesh}} respectively. The former exports nav areas in a selected set to a [[KeyValues]] text file, while <tt>nav_merge_mesh</tt> imports nav areas from a specified file &ndash; and selects them {{csgo|not}}.
{{note|Ladders and hiding spots are not exported or imported, so after importing, one may need to connect all ladders and <tt>nav_analyse</tt>.}}
Avoid loading a nav mesh on top of itself. To get rid of the duplicate mesh, one can delete the entire nav mesh and import again. When a nav area is imported, it may receive a different ID than in the text file.

The text file used by these commands can be edited to force custom nav area shapes such as skewed faces or diagonal connections that otherwise would be impossible to make.
{{Confirm|Is it unproblematic to do so?}}
{{warning|Degenerate areas are hard to select '''and (by proxy) remove''', so try not to make them!}}
{{clr|right}}
== See also ==
* [[Navigation Mesh Commands|Navigation Mesh Console Command Reference]]
* [[Keybinds for NavMesh editing 1]]

=== Left 4 Dead ===

* [[Left 4 Dead Navigation Meshes]]
* [[L4D Level Design/Nav Meshes]]
* [[L4D Level Design/Nav Flow]]
* [[L4D Level Design/Advanced Nav Editing]]

=== Team Fortress 2 ===
* [[Nav Mesh (Team Fortress 2)]]
* [[TFBot Technicalities]]

== External links ==
* Official forums for the bot system (down) - [http://web.archive.org/web/*/http://www.turtlerockstudios.com/forums/csbot/ Archived version].
* [https://www.editlife.net/tutorial.php?tutid=60 Waypointing for CS:S Bots/Hostages (Edit Life)]

[[Category:Source]]

[[Category:Counter-Strike: Source]]
[[Category:Counter-Strike: Global Offensive]]
[[Category:Team Fortress 2]]
[[Category: Left 4 Dead]]
[[Category: Left 4 Dead 2]]

[[Category:Level Design]]<!--Why?-->