View source for FGD

{{lang|FGD}}
[[FGD]] stands for '''F'''orge '''G'''ame '''D'''ata. It is the file extension for [[Hammer]]'s game definition files.  They define all of the [[entity|entities]] of a game so mappers can select them from within the editor. It is a key point to understand that an FGD is nothing more than a reference. You cannot create or modify entities by editing a FGD, you merely give [[Hammer]] different information about what it expects to find within the game. Sometimes editing reveals hidden or unused features or even entities, but they were always there and could be used even without the updated FGD. For Custom FGD files to work in Hammer, they must be added through Tools > Options.
{{note|FGDs are loaded in alphabetical order. If you do not use <code>@include "base.fgd"</code> at the top of your FGD and it is loaded before <code>base.fgd</code>, you will encounter errors.}}
{{todo|{{Source2|2}} adds some extra features to the FGD format. document those.}}

==History==
While Hammer was originally called [[Worldcraft]], it was developed under the name The Forge (hence the name Forge Game Data). Due to trademark issues, however, the name Forge couldn't be used for the final version of Hammer. Even so, the file extension stayed.

==File Format==
The FGD file follows a fairly simple format. It is a script file that sets up entity structures and relationships for Hammer. The various parts of the [[Half-Life 2.fgd|''Half-Life 2'' FGD]] (found in your SDK binary directory, for example: <code>(path_to_steam)/SteamApps/common/Source SDK Base 2013 Singleplayer/bin/</code>) are explained below.


=== Comments ===
Comments are defined simply by starting a line with '''//'''.  They can be preceded by spaces or tabs.
 //====== Copyright © 1996-2005, Valve Corporation, All rights reserved. =======
 //
 // Purpose: Half-Life 2 game definition file (.fgd) 
 //
 //=============================================================================

=== @Mapsize ===
This value defines the maximum usable area in [[Hammer]]. This '''visually''' changes the area in Hammer, but unless the game has been coded to allow this size, using anything beyond default values causes [[vbsp]] to crash.
  @mapsize(-16384, 16384)

=== @include ===
If the game you are writing your FGD for has a lot in common with another game ({{hl2|2}} and {{hl2dm|2}}, for example), you can <code>@include</code> a file that has all of the common structures defined in it. This allows your FGD to read all the data of that FGD.<br>
@Include can be nested. Meaning a game can include another game's FGD, which already includes the <code>base.fgd</code>. For example {{hl2dm|2}} has a FGD which @include's <code>halflife2.fgd</code>, which in turn @include's the <code>base.fgd</code>.<br>
The game or mod you are creating must ship with all FGD's that your own mod is including.
 @include "base.fgd"
{{Warning|This will include '''all''' entities of the included FGD, making them all appear in your Hammer map editor even if your game does not even have these entities coded.<br>
If you only need a few base classes and entities, it would be recommended to only copy those few into your own FGD.}}

=== Base Class ===
A <code>BaseClass</code> is used to setup structures that are used by several different entities via the <code>base(BaseClassName)</code> to the main definition line of the structure.<br>
The <code>BaseClass</code> structure is defined just like a normal entity in all respects. The only difference is that it doesn't appear in the entity lists in Hammer.
<source>
@BaseClass = Angles
[ 
	angles(angle) : "Pitch Yaw Roll (Y Z X)" : "0 0 0" : "This entity's orientation in the world. Pitch is rotation around the Y axis, " +
		"yaw is the rotation around the Z axis, roll is the rotation around the X axis."
]

@BaseClass = Origin
[ 
	origin(origin) : "Origin (X Y Z)" : : "The position of this entity's center in the world. Rotating entities typically rotate around their origin."
]
</source>

=== Point Class ===
Point classes are the entities you will be able to see in Hammer's entity list which can be placed 
<source>
@PointClass base(Targetname, Angles, Origin) studio("path/model.mdl") = example_entity_name : "example entity description, visible in Hammers 'help' Box. 
[

	Property_name_1(string) 	: "Example String Name"		: "Example"	: "Description"
	Property_name_2(integer) 	: "Example Interger Name"	: 15		: "Description"
	Property_name_3(float)		: "Example Float Name" 		: "1.5"		: "Description"
	Property_name_4(boolean)	: "Example Boolean Name"	: 1 		: "Description"
	
	Property_name_5(choices) : "second number" : 0 : "Your choice of numbers!" =
	[
		0 : "Default"
		1 : "Something"
		2 : "Another Thing"
	]

	spawnflags(flags) =
	[
		2 : "A flag" : 0       // 0 means the flag isn't ticked by default
		2 : "Another flag" : 1 // 1 means the flag is ticked by default
	]
	
	// Inputs
	input DoSomething(void) : "Do something"	
	// Outputs
	output OnSomethingHappened(void) : "Fires when something happens"
	output OnSomethingElse(void) : "Fires when something else happens"

]
</source>

Above is a generic example of an entity structure as defined in the FGD.<br>
The first line defines the class name of your entity, followed by class properties, name of the entity and a description for it.<br>
Everything in between the [ / ] brackets defines how the entity itself works. It defines keyvaules, flags and [[Inputs_and_Outputs| Inputs and Outputs]].<br>
Explanations of what each of these parameters do will be explained on this page, in order.

== Individual Entity listings ==
=== Classes ===
The class type of an entity tells Hammer how this entity can be placed.
{| class="wikitable"
|-
! Class Name !! Description
|-
| @PointClass|| The class type of an entity tells Hammer how this entity can be placed.
|-
| @PointClasssprite || This entity exists at a certain non-arbitrary point. It is typically referred to as a "[[point entity]]." The entities are placed within Hammer by using the Entity tool (Shift+E).
|-
| @NPCClasssprite || This is a special form of point entity tailored for [[NPC]] (non-player character) entities. It is useful in conjunction with the <code>npcclasssprite property type (see below).
|-
| @SolidClasssprite || This entity's area is defined by the solid (also referred to as a brush) that it is attached to.  It is typically referred to as a "brush entity" or "solid entity."
|-
| @KeyFrameClasssprite || Used for {{ent|move_rope}} and {{ent|keyframe_rope}}. This causes the <code>NextKeysprite property to be linked up when the entity is copied.
|-
| @MoveClasssprite || Used for {{ent|path_track}} and similar entities. This causes the <code>targetsprite property to be linked up when the entity is copied.
|-
| @FilterClasssprite || One of the special [[Filter|filter]] classes used to define what entities will be able to interact with each other in some way. This mainly causes the entity to be shown in properties with the <code>filterclasssprite type.
|}
=== Class Properties ===
Things between the Classtype declaration and the "= <entity name here>" help to define properties of the entity, how it will act and be displayed in Hammer. There are a number of different things that can used here. (More than one of these can be used, each separated by a space.)
{| class="wikitable"
|-
! Property !! Description
|-
| axis( ''property'' ) || Allows positioning two points joined by a line in the map. The property value is set to "x1 y1 z1, x2 y2 z2" by default.
|-
| base( ''BaseClass1, BaseClass2, …'' ) || This lets you attach previously defined <code>BaseClass</code>es (see above) to an entity. You can specify multiple <code>BaseClass</code>es, each separated by a comma.
|-
| bbox( ''min,max'' ) || Sets the size of the entity's bounding box.
|-
| color( ''red grn blu'' ) || This setting will change the color of the wireframe box in the Hammer 2D views. If this isn't present, the color will default to magenta. The values specified here are the RGB values of a color, and each number has a range from 0 to 255.
|-
| cylinder( ''color, start_key, start_name, start_radius, end_key, end_value, end_radius'' ) || Draw a cylinder between two entities. This is similar to <code>line()</code>, but with the addition of two ''<code>radius</code>'' properties that are looked up on the target entities. These define the size of the start and end of the cylinder.
|-
| frustum( ''fov,near,far,color, pitch_scale'' ) || Creates a rectangular cone extending from the entity. FOV defines the spread angle (0-180). Near and far define at what distances will be highlighted. The color value defines what color the cone will be shown with. Pitch_scale allows inverting the pitch angle when rendering the cone. The first four values must be property names, the last is a literal. If not specified, values are taken from <code>_fov</code>, <code>_nearplane</code>, <code>_farplane</code>, and <code>_light</code>, respectively. ''<code>pitch_scale</code>'' is set to -1.
|-
| halfgridsnap || When moving this entity, it will snap to half the current grid size. This is somewhat special as it takes no arguments or parentheses.
|-
| iconsprite( "''path/sprite.vmt''" ) || If this is used, the specified sprite will be shown in the Hammer 3D view instead of a flat-shaded colored box. This will work along-side the <code>studio()</code> or <code>studioprop()</code> commands. If no sprite name is set, it uses the <code>model</code> property. <code>scale</code>, <code>rendermode</code>, <code>_light</code> and <code>angles</code> properties affect the sprite.
|-
| lightcone( ''inner_fov, outer_fov, color, pitch_scale'' ) || Renders the cone used on {{ent|light_spot}} entities. ''<code>inner_fov</code>'' is the key for the innermost cone section, ''<code>outer_fov</code>'' is the outermost. ''<code>pitch_scale</code>'' allows inverting the pitch angle when rendering the cone. Values are taken from <code>_inner_cone</code>, <code>_cone</code>, and <code>_light</code>, respectively, if they aren't specified. This reads many other values corresponding to light_spot properties.
|-
| lightprop( "''path/model.mdl''" ) || Identical to <code>studioprop()</code>, except that the pitch of the model is inverted.
|-
| line( ''color, start_key, start_value, end_key, end_value'' ) || Draws a line between two entities. The ''<code>value</code>'' properties in this entity give the names to look for in the ''<code>key</code>'' property on other entities. ''<code>key</code>'' is usually set to <code>targetname</code>. The color sets the color of the line when the entity is not selected. The second entity defaults to this one if not set.
|-
| obb( ''min,max'' ) || Identical to <code>bbox</code> but oriented to the entity's angles.
|-
| origin( ''property'' ) || Allows positioning a vector property in the map. 
|-
| sidelist( ''sides'' ) || Highlight brush faces listed in the given property (as a space-seperated ID list). If not specified, the property used is <code>sides</code>.
|-
| size( ''-x,-y,-z,+x,+y,+z'' ) || Defines the size of the default cube used when no model or sprite is specified. 
|-
| sphere( ''propertyname'' ) || If an entity has a radius of effect, like a sound for example, a sphere will be displayed in Hammer's 2D and 3D views. You need to specify the property that will control the sphere size. If no property is specified, it will look for a <code>radius</code> property. 
|-
| studio( "''path/model.mdl''" ) || Identical to <code>studioprop()</code>, but the bounding box around the entity will ignore this model. This is useful for entities that don't render the model ingame.
|-
| studioprop( "''path/model.mdl''" ) || If this is used, the entity will be displayed in the 3D view as the specified model. If no model is specified, the value of the entity's <code>model</code> property will be used, if available (Unless hardcoded). Multiple models can be defined.{{note|If you have an entity with the "angles" property that you want to be able to rotate in Hammer using the mouse (as opposed to only through property editing), you may need to add this modifier.}}{{note|The appearance is affected by the <code>skin</code> and <code>rendercolor</code> properties, similar to {{ent|prop_dynamic}}.}}
|-
| vecline( ''property'' ) || Allows positioning a vector property in the map. This also draws a line from the entity to the position.
|-
| wirebox( ''min,max'' ) || Draws a bounding box for two properties. <code>origin()</code> helpers should be defined as well to allow moving the points.
|-
| worldtext()<br>{{csgobranch|only}} || Displays the contents of the <code>message</code> keyvalue in the 3D viewport.
|}
The following helpers take no arguments and are special-cased for specific entity types:
{| class="wikitable"
|-
! Property !! Description
|-
| decal() || Renders decals on nearby surfaces. This uses the '''texture''' property to set the material to use.
|-
| overlay() || Renders overlays on a surface. (For {{ent|info_overlay}})
|-
| overlay_transition() || Renders overlays on the intersections between water and the shore. (For {{ent|info_overlay_transition}})
|-
| light() || Present on {{ent|light}}; its use is unknown. {{todo|Figure out what this does.}}
|-
| sprite() || Renders the sprite material specified in the <code>model</code> keyvalue ({{ent|env_sprite}} and variants). For entity icons, use <code>iconsprite</code>.
|-
| sweptplayerhull() || Draws 32x32x72-sized rectangular prisms at two points ('''point0''' and '''point1'''), then links corners to show the space needed for one rectangle to move to the other's position. This also adds <code>origin()</code> helpers for those properties.
|-
| instance() || Renders the [[func_instance|instance]] in the map. It also generates additional properties dynamically corresponding to the instance parameters.
|-
| quadbounds() || Used for {{ent|func_breakable_surf}}. Automatically sets the 4 corners of the textured face on save. {{todo|Does this also control the "error" keyvalue?}}
|}
=== Entity Description ===
[[File:Hammer entity help.jpg|300px|thumb|right|The entity help box containing the message written on the left.]]
The entity description is a very important thing, as it the one single piece of help you can see in Hammer without consulting any website or developer, by pressing the "Help" button.<br>
Each line of a description may not exceed 125 letters, in which case you must terminate the line and append a + at the end to start a new line in the FGD.<br>
You may write '''\n''' To insert a line break, where hammer will start writing on a new line. You may also enter '''\n \n''' to skip one line entirely.<br>
{{warning|Quotation marks (") are not allowed inside the description, as this will terminate the string. Use Apostrophes (') instead.}}
<syntaxhighlight lang=text highlight=2-5>
@PointClass = example_entity :
    "This is an example description for this example entity. It will appear in the help dialog for this entity.\n " +
    "Sometimes a description string gets very long, which cause errors. In which case we need to terminate the line and " +
    "append a + to the end, telling Hammer the next line is a continuation of the current line. Like in this example.\n " +
    "Note how the Quotation mark appears after a space at the end of the line. Without it, the words between lines get merged"
[
    (entity properties go here)
]
</syntaxhighlight>

=== Entity Properties ===
Everything between the main set of [ / ] brackets is used to define the entity's properties, including their inputs and outputs. Individual property structures consist of a name, a type declaration, a display name, a default value, and a description.<br>
The most common properties are:

{| class="wikitable"
|-
! Property !! Description
|-
| string || This creates a property of the string type.  
|-
| integer || This creates a property of the integer type.
|-
| float || This creates a property of the float type. Although it deals with numbers, the structure of it is similar to the string type.  The default value must have quotes around it.
|-
| boolean<br> {{as|since}}{{Gmod|also}} ||This creates a property of the boolean type, with a dropdown for yes/no. For older versions of Hammer, use choices instead.
|-
| flags || The flags property type lets you setup what will appear in the Flags portion of the entity property dialog. It is set up similar to the choices property type. The flags are all powers of 2 (2⁰=1, 2¹=2, 2²=4, etc.), and their values are either 0 (off) or 1 (on). If no default is specified for a flag, it is considered to be off.
|-
| choices || A property of this type lets you setup a number of distinct choices.
|}
<code>Flags</code> and <code>Choices</code> follow a slightly different format. They do not function as input/output types.<br>

<source>
Property_name_1(string) 	: "Example String Name"		: "Example"	: "Keyvalue Description"
Property_name_2(integer) 	: "Example Interger Name"	: 15		: "Keyvalue Description"
Property_name_3(float)		: "Example Float Name" 		: "1.5"		: "Keyvalue Description"
Property_name_4(boolean)	: "Example Boolean Name"	: 1 		: "Keyvalue Description"

</source>
{{Note|The third value, depicted here as "Example", 15, 1.5 and 1 are the default values. Those will always be there when the entity is being placed. Some string values can also be left empty by using "". in which case there is no default value at all.}}
{{Note|Unlike entity descriptions, keyvalue descriptions can not make use of '''\n'''. Only workaround is to manually find out how many spaces you need to fill up a line in the description window.}}
'''Choices:'''
<pre>
Property_name_5(choices) : "Display name" : "1" =
[
    0 : "something"
    1 : "something else (default)"
    2 : "something completely different"
]
</pre>
:You can also use strings (or floats) as values, instead of integers, like this:
<pre>
Property_name_5(choices) : "Model used" : "models/something02.mdl" =
[
    "models/something01.mdl" : "something"
    "models/something02.mdl" : "something else (default)"
    "models/something03.mdl" : "something completely different"
]
</pre>

'''Flags'''<br>
The <code>flags</code> property type lets you setup what will appear in the Flags portion of the entity property dialog. It is set up similar to the <code>choices</code> property type.  The flags are all powers of 2 (2⁰=1, 2¹=2, 2²=4, etc.), and their values are either 0 (off) or 1 (on).  If no default is specified for a flag, it is considered to be off.
<pre>
spawnflags(flags) =
[
    1 : "something clever" : 1
    2 : "something else" : 0
    4 : "you said what now?" : 0
    8 : "nothing" : 1
]
</pre>
{{note|"spawnflags" is always the name of this property. Creating a flags-type property with any other name will result in it appearing as a normal integer keyvalue.}}


There are also a number of special purpose property types that modify the entity properties dialog UI to allow for easy browsing for files or easier manipulation of complex properties (like colors or angles).
{| class="wikitable"
|-
! Property !! Description
|-
| angle || Adds an angle widget for this property to the entity dialog UI.
|-
| angle_negative_pitch || Identical to <code>angle</code>, except the pitch is inverted.
|-
| axis || Adds a relative 2-point axis helper.
|-
| {{ent|color255}} || Adds a button that brings up the color choosing UI, which takes the color you select and translated it into the three-number RGB value. Allows extra parameters (e.g., brightness).
|-
| color1 || Adds a color button, but uses a float [0,1] instead of an integer (0,255). Allows extra parameters (e.g., brightness).
|-
| decal || Identical to <code>material</code>, except it will automatically replace your search filter with <code>decals/</code> when opening the material browser.{{note|Sometimes, the material you want will be in <code>overlays/</code> or in another folder entirely.}}
|-
| filterclass || Marks property as being the name of the filter to use.
|-
| instance_file || Adds a button that brings up the file browser, letting you browse for instance files.
|-
| instance_parm || Used in {{ent|func_instance_parms}} to define fixup variables.
|-
| instance_variable || Used in {{ent|func_instance}} to set fixup variables.
|-
| material || Adds a button that brings up the material browser.
|-
| node_dest || adds an eyedropper to select a node in the 3d view
|-
| node_id</code> <br>{{as|since}} || On [[node]]s, this is used for the Node ID keyvalue to automatically increment it with each consecutive node placed. Does not appear to function when used on other entities.
|-
| npcclass || Adds a drop-down selection list populated by entities of the NPCClass type.
|-
| origin || origin
|-
| particlesystem</code> <br>{{as|since}} || Adds a button that brings up the particle browser, letting you browse for particle systems.{{bugfix|The particle browser cannot read files from [[VPK]]s!|You will need to extract the game's [[PCF]] files for anything to appear.}}
|-
| pointentityclass || Adds a drop-down selection list populated by entities of the <code>PointClass</code> type.
|-
| scene || Adds a button that brings up the sound browser, letting you browse for scene files.
|-
| script</code> <br>{{l4d2|since}} || Adds a button that brings up the file browser, letting you browse for [[VScript]]s.
|-
| scriptlist</code> <br>{{l4d2|since}} || Adds a button that brings up a list of VScripts with buttons to add/remove scripts and open each file.{{note|Vscript browser is most of the time empty. Instead a Vscript name without extension will work just fine.}}
|-
| sidelist || Adds a side selection eyedropper that allows you to choose sides (multiple with {{key|Ctrl}}).
|-
| sound || Adds a button that brings up the sound browser, letting you browse for soundscripts or raw sounds.
|-
| {{sprite}} || identical to <code>material</code>, except it will automatically replace your search filter with <code>sprites/</code> when opening the material browser, and it will add <code>.vmt</code> to the end of the material name.
|-
| studio || Adds a button that brings up the model browser.
|-
| target_destination || Marks property as another entity's <code>targetname</code>.
|-
| target_name_or_class || Marks property as another entity's <code>targetname</code> or <code>classname</code>.
|-
| target_source || Marks property as being the name that other entities may target.
|-
| vecline || Adds an absolute 1-point axis helper, similar to the origin marker.
|-
| vector || 3D vector property.
|}

== Other File Sections ==
=== Material Exclusion Lists ===
These lists define paths that Hammer's Material Browser will not use when presenting you with a palette of textures to choose from. It should have no effect on what files are actually available to a custom map.
{{note|Any folder called <code>models/</code> will always be excluded, regardless of what is set here.}}
<source>
@MaterialExclusion
[
    // Names of the sub-directories we don't want to load materials from
    "debug"
    "engine"
    "hud"
    "vgui"
]
</source>

=== Customizing Auto-Visgroups ===
This permits customizing the automatic Visgroups tab of the [[Hammer_Filter_Control_Toolbar|Filter Control]] toolbar. The first title is the name of the "parent," and the next is the "children." Finally comes a list of entity classes that will be placed in the visgroup.<br>
If the parent already exists, the new entry will be merged with the previous ones (including the default list of groups). This permits creating trees with multiple levels of grouping. If a visgroup becomes entirely empty, it will not appear in the list.<br>
You may add entities to existing groups if the "Parent" of the autovisgroup is the name of an existing group, like "World Details". For example, you could add {{ent|func_brush}} to the list "World Details".<br>
{{warning|Having too many AutoVisGroups can cause hammer to lag on startup and during runtime.}}
<source>
@AutoVisGroup = "Brushes"
[
    "Triggers"
    [
        "trigger_once"
        "trigger_multiple"
    ]
    "Tool Brushes"
    [
        "func_areaportal"
        "func_viscluster"
    ] 
]

@AutoVisGroup = "Tool Brushes"
[
    "Vis Clusters"
    [
        "func_viscluster"
    ]
]
</source>

== Source 2 Additions ==
The following things have been found in {{Source2|2}} FGD files. These will not work in Source 1.<br>
{{todo|Find more things that are not listed here. Explain what these do. So far only occurrences of {{hla}} FGD's have been pasted here for documenting them.}}

=== Classes ===
{| class="wikitable"
|-
! Class Name !! Description
|-
| @OverrideClass || This can be used to Overwrite values of existing entities, or add more to an existing entity if an @included FGD.
|-
| @CableClass || {{todo|Explain what this does.}}<br>{{hla}} Seen in models_gamedata.fgd
|-
| @PathClass || {{todo|Explain what this does.}}<br>{{hla}} Seen in base.fgd
|}

==== Example of these Classes ====
'''@OverrideClass'''
This can be used to quite literally overwrite data of existing entities, as well as adding new keyvalues and inputs/outputs.
{{ExpandBox|<source>
// Add an override of player start in order to add it to the ui.
@OverrideClass 
	metadata
	{
		entity_tool_name = "Player Start" 
		entity_tool_group = "Player"
		entity_tool_tip = "Entity which specifies where the player will start."
	}
= info_player_start :
[
]

@OverrideClass = npc_cscanner
[
	//Adds one single input to the npc_cscanner entity, which already existed in HL2 and is in halflife2.fgd
	//Doing this is easier than completely redefining the entire entity.
	input SpawnAsAltScanner(void): "Spawns the Russell skin/bodygroup scanner"
]
</source>}}

''' @CableClass '''
{{ExpandBox|<source>
@CableClass = cable_static
[
]
@CableClass base( Targetname, Parentname, Global, RenderFields, Glow, EnableDisable) sphere(fademindist) sphere(fademaxdist) = cable_dynamic
[
	secondary_material(material) : "Secondary Material" : "" : "Optional secondary material, can be selected using Skin(1)"
	lightingorigin(target_destination) : "Lighting Origin" : "" : "Select an entity to specify a location to sample lighting from, instead of using this entity's origin."
	disableshadows(boolean) [ group="Misc" ] : "Disable Shadows" : 0 : "Used to disable dynamic shadows on this entity."

	// Inputs
	input TurnOn(void) : "Make the prop visible."
	input TurnOff(void) : "Make the prop invisible."
	input Skin(integer) : "Changes the model skin to the specified number."
	input EnableCollision(void) : "Enable collision on the prop."
	input DisableCollision(void) : "Disable collision on the prop."
	input SetNavIgnore(boolean) : "Enable and disable NAVIgnore on the prop."
	input DisableShadow(void) : "Turn shadow off."
	input EnableShadow(void) : "Turn shadow on."
	input AlternativeSorting(bool) : "Used to attempt to fix sorting problems when rendering. True activates, false deactivates"
	input SetRenderAttribute(string) : "Set the value of a render attribute used in material dynamic expressions. Examples: $myfloat=0.25 $myfloat4=1.0,0.0,1.0,1.0"
]
</Source>}}

''' @PathClass '''
{{ExpandBox|<source>
@PathClass base(Targetname) tags( Particles ) particle_rope() 
	metadata
	{
		default_interpolation = "linear"
	}
= path_particle_rope
[
	effect_name(particlesystem) [report] : "Particle System Name" : "particles/entity/path_particle_cable_default.vpcf"
	start_active(boolean) : "Start Active" : 1 : "Will the particle system be visible on spawn"
	max_simulation_time(float) : "Max Time To Simulate" : 0 : "Max number of seconds to run the particle simulation for. A value of 0 means run the simulation indefinitely."
	particle_spacing(float) : "Spacing" : 32 : "Units between the individual partcles in the rope simulation."
	slack(float) : "Slack" : "0.5" : "Controls the amount the rope will drop between path nodes. Generally between 0.0 and 1.0, the value is a multiplier on the distance that particles on path can seperate relative to their initial distance."
	radius(float) : "Radius" : "4.0" : "Radius of the rope."
	static_collision( bool ) : "Create Static Collision" : "0" : "Create a static physics representation of the path. Note the collision is generated based on the path, movement applied by the particle system will not be included."
	surface_properties(surface_properties) : "Surface Properties" : "" : "Surface properties to apply to the static collision if generated"
	color_tint(color255) : "Color Tint" : "255 255 255"
			
	// Inputs
	input Start(void) : "Tell the particle system to start emitting."
	input Stop(void) : "Tell the particle system to stop emitting."
	input StopPlayEndCap(void) : "Tell the particle system to stop emitting and play its End Cap Effect."
	input DestroyImmediately(void) : "Destroy the particle system and remove all particles immediately."
	input SetRadius( float ) : "Set the radius parameter provided the particle system"
	input SetSlack( float ) : "Set the slack parameter which may be used by the particle system to determine how much the rope droops."
	input DisablePin( string ) : "Disable the contraint which pins a particle to the specified path node."
]
</source>}}
=== Other commands ===
{| class="wikitable"
|-
! Class Name !! Description
|-
| @Exclude || This can exclude individual entities that are in @include'd FGD's. One entity per line
|-
| @EntityGroup || {{todo|Explain what this does.}}<br>{{hla}} Seen in hlvr.fgd
|-
| @struct || {{todo|Explain what this does.}}<br>{{hla}} Seen in workshop_addoninfo.fgd
|-
| @ModelGameData || {{todo|Explain what this does.}}<br>{{hla}} Seen in models_gamedata.fgd<br>Seems to work simillar to [[$keyvalues]].
|-
| @ModelBreakCommand || {{todo|Explain what this does.}}<br>{{hla}} Seen in models_gamedata.fgd<br>Seems to work simillar to [[$collisiontext]]
|-
| @ModelAnimEvent  || {{todo|Explain what this does.}}<br>{{hla}} Seen in models_base.fgd<br>Seems to work simillar to [[Animation_Events]] in [[$sequence|Sequences]].
|-
| Metadata<br> {<br> entity_tool_name = <string><br> entity_tool_tip = <string><br> entity_tool_group = <string><br> } || {{todo|Explain what this does.}}<br>{{hla}} Seen in hlvr.fgd
|-
| Deprecated() || Marks a property as depracated and no longer in use.
|}
==== Examples of these commands ====
Below are expandable examples of the above listed commands.<br>
We currently do not have any more good information on what these commands do, but at least we have examples of how to use them.

'''@exclude'''
{{ExpandBox|<source>
// Excluded entities. These are entities that are included from lower level fgd files that aren't 
// functional or useful in this mod. Excluding them removes them from the list of entities aviable 
// in Hammer or any other tool that loads the fgd. If support is added for any of the entities the 
// exclude can simply be removed.

// These entities have been excluded because are deprecated light entities which are
// explictly not supported, don't add these back unless you are working on lighting.
@exclude color_correction_volume
@exclude env_fog_controller
@exclude env_time_of_day
@exclude env_lightglow
@exclude env_particlelight
@exclude env_sun
@exclude fog_volume
@exclude info_lighting
@exclude light_dynamic
@exclude light_irradvolume
@exclude point_spotlight
@exclude postprocess_controller
@exclude shadow_control
</source>}}

'''@EntityGroup'''
{{ExpandBox|<source>
// Entity groups. This list specifies which entity groups will show up in the entity tool and in what
// order. If an entity specifies a group that is not in this list it will not be displayed in the tool.
// This allows the mod specific fgd to control the ui.
@EntityGroup "Player" {	start_expanded = true }
@EntityGroup "Lighting" { start_expanded = true }
@EntityGroup "Fog & Sky" { start_expanded = true }
@EntityGroup "NPCs" { start_expanded = true }
@EntityGroup "Items"
@EntityGroup "Ammo"
@EntityGroup "Logic"
</source>}}

'''@Struct'''
{{ExpandBox|<source>
@struct = map_extension :
[
	parent_map(string) : "Parent Map" : "" : "This is the map that you are extending (eg. <font color='cyan'><tt>a1_intro_world</tt></font>) - when it loads, your extension map will also be loaded."
	extension_map(string) : "Extension Map" : "" : "Name of a map to overlay on top of the parent map."
]
</source>}}

'''@ModelGameData'''
{{ExpandBox|<source>
@ModelGameData = prop_data
[
	base(propdataname) 		: "Base Prop" : : "Base keys (entry from propdata.txt)"
	allowstatic(boolean) 	: "Allow As Static Prop" : 0
	bakelighting(boolean)	: "Bake Lighting As Static Prop" : 1
	damage_table(choices) 	: "Damage Table" : "" : "" =
	[
		""						:	"Inherit Default"
		"player"				:	"Player"
		"player_vehicle"		:	"Player Vehicle"
		"npc"					:	"NPC"
		"glass"					:	"Glass"
		"props"					:	"Props"
		"prevent_impact_damage"	:	"Prevent All Impact Damage"
	]
	dmg.bullets(float) 		: "Damage Bullets" : -1
	dmg.club(float) 		: "Damage Club" : -1
	dmg.explosive(float) 	: "Damage Explosive" : -1
	dmg.fire(float) 		: "Damage Fire" : -1
	health(float) 			: "Health" : -1
	spawn_motion_disabled(boolean) : "Spawn as Motion-Disabled" : 0
]
</source>}}

'''@ModelBreakCommand'''
{{ExpandBox|<source>
@ModelBreakCommand base(base_break_force)
= break_uniform_burst : "Applies a radial burst to breakpieces outwards from the influence point (default is the origin of the model)"
[
	burst_scale(float) [ min="0", max="500" ]		: "Burst Scale"					: 0		: "Velocity added to each piece (radially away from the influence point)"
	burst_randomize(float) [ min="0", max="500" ]	: "Burst Randomize"				: 0		: "Magnitude of random vector that will be added to the burst velocity"
]

@ModelBreakCommand base(base_break_force)
= break_flip_pieces : "Applies an angular 'flip' to breakpieces (like objects tipping over from an explosion or flower petals opening) causing them to tip outwards from the influence point (default is the origin of the model)"
[
	burst_scale(float) [ min="-500", max="500" ]	: "Flip Scale"					: 0		: "Angular velocity added to each piece (Positive value will cause pieces to flip 'head-first' away from the influence point, negative is 'feet-first')"
	burst_randomize(float) [ min="0", max="500" ]	: "Flip Randomize"				: 0		: "Largest possible value that will be randomly added/removed to Flip Scale for each piece"
]

@ModelBreakCommand base(base_break_force)
= break_twist_pieces : "Applies an angular 'twist' to breakpieces, causing them to roll around the radial axis outward from the influence point (default is the origin of the model)"
[
	burst_scale(float) [ min="-500", max="500" ]	: "Twist Scale"					: 0		: "Angular velocity added to each piece"
	burst_randomize(float) [ min="0", max="500" ]	: "Twist Randomize"				: 0		: "Largest possible value that will be randomly added/removed to Twist Scale for each piece"
]
</source>}}

'''@ModelAnimEvent'''
{{ExpandBox|<source>
@ModelAnimEvent = AE_CL_PLAYSOUND_ATTACHMENT
[
	name(sound) [report] : "Sound"
	attachment(model_attachment) : "Attachment"
	stop_on_seq_change(bool) : "Auto-stop on sequence change or death" : "0"
	use_layer_sequence(bool) : "Use Layer Sequence" : "0"
	tags(string)				: "Tags"
]
@ModelAnimEvent = AE_COMPANION_PRODUCE_FLARE 
[
	attachment(model_attachment) : "Attachment"
]

@ModelAnimEvent = AE_STRIDER_SHOOTMINIGUN 
[
	target(string) : "Target"
]
</source>}}

'''Metadata'''
{{ExpandBox|<syntaxhighlight lang=text highlight=2-7>
@PointClass base(BasePropPhysics, Targetname, Parentname ) model( "models/props_combine/health_charger/health_vial.vmdl" )
	metadata
	{
		entity_tool_name = "Health Station Vial"
		entity_tool_tip = "Vial used to power a health station"
		entity_tool_group = "Items"
	}
= item_hlvr_health_station_vial : "Health Vial"
[
	vial_level(float) : "Health Vial Level (0-1)" : "1" : "Amount of health the vial starts with."
]</syntaxhighlight>}}

'''deprecated()'''
{{ExpandBox|<source>
@ModelAnimEvent deprecated() = AE_STRIDER_FOOTSTEP_LEFT [ ]
@ModelAnimEvent deprecated() = AE_STRIDER_FOOTSTEP_RIGHT [ ]
@ModelAnimEvent deprecated() = AE_STRIDER_FOOTSTEP_BACK [ ]
@ModelAnimEvent deprecated() = AE_MARINE_FOOTSTEP [ ]
@ModelAnimEvent deprecated() = AE_FOOTSTEP_LEFT [ ]
@ModelAnimEvent deprecated() = AE_FOOTSTEP_RIGHT [ ]
@ModelAnimEvent deprecated() = AE_SV_FOOTSTEP_LEFT [ ]
@ModelAnimEvent deprecated() = AE_SV_FOOTSTEP_RIGHT [ ]
@ModelAnimEvent deprecated() = AE_ANTLION_FOOTSTEP_HEAVY [ ]
@ModelAnimEvent deprecated() = AE_ANTLION_FOOTSTEP_SOFT [ ]
</source>}}

[[Category:FGD]][[Category:File formats]][[category:Glossary]][[category:Level Design]]

== External Links ==
* [https://github.com/Pinsplash/SEFGD SE FGD's] Updated FGD's for some Valve games, made by Pinsplash.
* [https://github.com/Crowbar-Sledgehammer/forge-game-data-language Forge Game Data Language] <code>.fgd</code> syntax highlighting available in textmate format (SublimeText Compatible)