env_headcrabcanister
(Redirected from Sk env headcrabcanister shake radius vehicle)


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env_headcrabcanister
is a point entity available in the Half-Life 2 series. The canister is a mortar shell containing a payload of headcrabs. The mortar shell inflicts damage within a radius of where it lands and releases headcrabs after impact. Inputs and keyvalues offer control over impact damage and when the headcrabs are released, among other options.
For an example of their use, see the shantytown in d1_canals_05
.
This entity is also in the code for . Its functionality is not guaranteed.

CEnvHeadcrabCanister
class, defined in theenv_headcrabcanister.cpp
file.
ConVars/Commands
ConVar/Command | Parameters or default value | Descriptor | Effect |
---|---|---|---|
sk_env_headcrabcanister_shake_amplitude | 50 | Arbitrary decimal (float) | Crash effect's shake amplitude. Though the default is 50, the shake amplitude can only go up to 16. |
sk_env_headcrabcanister_shake_radius | 1024 | Hammer units | Radius the player must be within for the screen shake effect to occur. Shake amplitude is gradually decreased the farther away from the explosion the player is. |
sk_env_headcrabcanister_shake_radius_vehicle | 2500 | Hammer units | As above, but when in a vehicle. |
Flags
- 1: No Impact Sound
- 2: No Launch Sound
- 4096: Start Impacted
- 8192: Land at initial position
- 16384: Wait for input to open
- 32768: Wait for input to spawn headcrabs
- 65536: No smoke
- 131072: No shake
- 262144: Remove on impact
- 524288: No impact effects
Keyvalues
- Which headcrab to Spawn? (HeadcrabType) <choices>
- Select which headcrab will jump out the canister.
- 0: Normal headcrabs
- 1: Fast Headcrabs
- 2: Poison Headcrabs
- Headcrab count (HeadcrabCount) <integer>
- Number of headcrabs to spawn on impact.
- Min Refire time (MinSkyboxRefireTime) <float>
- Min number of seconds before the canister is refired. This will only work for canisters placed in the skybox.
- Max Refire time (MaxSkyboxRefireTime) <float>
- Max number of seconds before the canister is refired. This will only work for canisters placed in the skybox.
- Canister count (SkyboxCannisterCount) <integer>
- Number of canisters to produce and fire across the skybox. The target should be positioned inside the skybox. 0 means fire continuously, forever.
- Impact damage (Damage) <float>
- Max damage the canister applies on impact.
- Impact damage Radius (DamageRadius) <float>
- Max radius of the impact damage for the canister.
- Smoke duration (SmokeLifetime) <float>
- Duration that the canister smokes. -1 means always smoke.
- Launch Position Name (LaunchPositionName) <targetname>
- If the canister should launch to its origin from another point within the world, this should specify an
info_target
at the launch origin.
- Flight Speed (FlightSpeed) <float>
- Speed to fly through the air.
- Flight Time (FlightTime) <float>
- Time to fly through the air in seconds.
- Starting Height (StartingHeight) <float>
- Relative height from the landing position at which the canister should be launched. Positive values mean launch it above the impact point, negative values mean launch it below.
BaseAnimating:
- Skin
(skin or ModelSkin
<integer>)
- Some models have multiple skins. This value selects from the index, starting with 0.
- Collisions
(solid)
<choices> - Method of collision for this entity.
- Body Group
(body or SetBodyGroup)
<integer> !FGD - Sets the the active
$bodygroup
.
- Model Index
(modelindex)
<short> !FGD - Given the number index from dumping the
cl_precacheinfo modelprecache
table, sets entity model to the index.Warning:If an entity has animations that will be played, then the set model also must have its own sequences, else the game crashes.
- Model Scale
(modelscale)
<float> (in all games since)
- A multiplier for the size of the model. Negative values are accepted. Does not alter the physics collisions in most cases, however.
Warning:Negative or extremely high values can cause crashes!
Note:Scale may not appear in
Hammer 4.x, but will appear in-game (tested in
). This is fixed in
Hammer++.
DXLevelChoice:
- Minimum DX Level
(mindxlevel)
<choices> (removed since)
- The entity will not exist if the engine is running outside the given range of DirectX Versions.
Warning:If these are used, the object may break when the user switches their DirectX settings.
Animating
- Sequence
(sequence)
<integer> !FGD - Default animation sequence for the model to be playing after spawning.
- Playback Rate
(playbackrate)
<float> !FGD - A multiplier of the framerate at which animations are played, negative values are accepted. Default is 1.0.
- Texture Frame
(texframeindex)
<integer> !FGD - The initial frame number for all animated textures on this entity.
Effects - Render
- Start Fade Distance
(fademindist)
<float> - Distance at which the entity starts fading. If 0 or less, the entity will disappear instantly when end fade is hit. The value will scale appropriately if the entity is in a 3D Skybox.
- End Fade Distance
(fademaxdist)
<float> - Distance at which the entity ends fading. If 0 or less, the entity won't disappear at all. The value will scale appropriately if the entity is in a 3D Skybox.
- Fade Scale
(fadescale)
<float> - If specified in the
worldspawn
, or if the engine is running below DirectX 8, entities will fade out even if the fade distances above aren't specified. This value gives more control over when this happens: numbers smaller than 1 cause the entity to fade out at further distances, and greater than 1 cause it to fade out at closer distances. Using 0 turns off the forced fade altogether. See also$noforcedfade
.
- FX Amount/Transparency (0–255)
(renderamt)
<integer> - Transparency amount, requires a Render Mode other than Normal. 0 is invisible, 255 is fully visible.
- Render Color (R G B)
(rendercolor)
<color255> - Color tint.
- Render FX
(renderfx)
<choices> - Various somewhat legacy alpha effects.


- 0: None
- 1: Slow Pulse (varies alpha by ±16 over a period of 1.5 s)
- 2: Fast Pulse (varies alpha by ±16 over a period of 0.4 s)
- 3: Slow Wide Pulse (varies alpha by ±64 over a period of 1.5 s)
- 4: Fast Wide Pulse (varies alpha by ±64 over a period of 0.4 s)
- 5: Slow Fade Away (decreases alpha by -1 per frame/(in all games since
) Fades out over 4 s)
- 6: Fast Fade Away (decreases alpha by -4 per frame/(in all games since
) Fades out over 1 s)
- 7: Slow Become Solid (increases alpha by +1 per frame/(in all games since
) Fades in over 4 s)
- 8: Fast Become Solid (increases alpha by +4 per frame)
- 9: Slow Strobe (transparent 0.8 s, visible 0.8 s, repeat)
- 10: Fast Strobe (transparent 0.2 s, visible 0.2 s, repeat)
- 11: Faster Strobe (transparent 0.09 s, visible 0.09 s, repeat)
- 12: Slow Flicker (transparent 0.18 s, visible 1.5 s, repeat)
- 13: Fast Flicker (transparent 0.14 s, visible 0.2 s, repeat)
- 14: Constant Glow ("NoDissipation;" purpose uncertain—for sprites?) (not in
)
- 15: Distort (causes unnatural flickering and position shifting)
- 16: Fade In (instant; not very useful outside of code)
- 17: Scale Up ("Explode"/"scale up really big!" causes wild stretching of model parts) (in
)
Confirm:which branches/games is it available in, and where does it do what?
- 18: Glow Shell (purpose unclear) (in all games since
) (not in
)
Confirm:what does this do? and which games is it in?
- 19: Clamp Minimum Scale ("keep this sprite from getting very small (SPRITES only!)") (not in
)
- 20: Environmental Rain ("for environmental rendermode, make rain") (in
) (not in
)
Confirm:which games? may be nonfunctional.
- 21: Environmental Snow ("for environmental rendermode, make snow") (in
) (not in
)
Confirm:which games? may be nonfunctional.
- 22: Spotlight FX ("TEST CODE for experimental spotlight") (in
) (not in
)
- 23: Ragdoll ("HACKHACK: TEST CODE for signalling death of a ragdoll character;" ragdolls an entity but doesn't kill it) (in
) (not in
)
Confirm:which games? may be nonfunctional?
- 24: Fade Wider Pulse (varies alpha by ±255 over a period over a period of 0.26 s) (in
) (not in
)
- 25:
kRenderFXMax
/Fade Near
Todo: what does this do? may be nonfunctional
- Render Mode
(rendermode)
<choices> - Set a non-standard rendering mode on this entity.
Effects - Environment
- Disable Shadows
(disableshadows)
<boolean> - Prevent the entity from creating cheap render-to-texture shadows. Does not affect shadow mapping.
- Disable Receiving Shadows
(disablereceiveshadows)
<boolean> - Prevent the entity from receiving shadows on itself.
- Shadow Cast Distance
(shadowcastdist)
<integer> - Sets how far the entity casts dynamic shadows. 0 means default distance from the
shadow_control
entity.
- Lighting Origin
(LightingOrigin)
<targetname> - Select an entity (not
info_lighting
!) from which to sample lighting instead of the entity's origin. Lighting Origin Offset(not in(LightingOriginHack)
<targetname>) !FGD
- Deprecated. The
info_lighting_relative
from which to sample lighting instead of the entity's origin. Use Lighting Origin instead.
Base:
- Parent
(parentname)
<targetname> - Maintain the same initial offset to this entity. An attachment point can also be used if separated by a comma at the end. (
parentname [targetname],[attachment]
)Tip:Entities transition to the next map with their parents
Tip:
phys_constraint
can be used as a workaround if parenting fails.
- Origin (X Y Z)
(origin)
<coordinates> - The position of this entity's center in the world. Rotating entities typically rotate around their origin.
Note:Hammer does not move the entities accordingly only in the editor.
- Pitch Yaw Roll (X Y Z)
(angles)
<angle> - 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.
Note:This works on brush entities, although Hammer doesn't show the new angles.
- Classname
(classname)
<string> !FGD - Determines the characteristics of the entity before it spawns.
Note:Changing this on runtime still has use, like making matching an entry in S_PreserveEnts will persist the entity on new rounds!
Inputs
FireCanister
- Fires the canister.
OpenCanister
- Opens the canister (must be called after the
OnImpacted
output is fired).
SpawnHeadcrabs
- Spawns headcrabs (must be called after the
OnImpacted
output is fired and afterOpenCanister
is triggered, if the Wait for Input to open' flag is checked).)
StopSmoke
- Causes the smoke effect to stop.
Model:
SetBodyGroup
<integer>- Sets the the active
$bodygroup
.
Ignite
- Makes the entity catch on fire indefinitely.
IgniteLifetime
<float>- Makes the entity catch on fire for a given amount of time.
IgniteNumHitboxFires
<integer> (removed since)
- Makes the entity catch on fire with a given number of hitbox fire particles. Does not function correctly in
onward.
IgniteHitboxFireScale
<float> (removed since)
- Makes the entity catch on fire with a given scale for hitbox fire particles. Does not function correctly in
onward.
BecomeRagdoll
- Kills the entity and creates a client-side ragdoll from the model. Input is only passed if the model contains
$collisionjoints
. For other models,phys_convert
can be used instead.
SetLightingOrigin
<targetname>- Sets the entity's lighting origin to use this entity's position.
(removed sinceSetLightingOriginHack
<targetname>)
- Deprecated. Offsets the entity's lighting origin by their distance from an
info_lighting_relative
. UseSetLightingOrigin
instead.
fademindist
<float>- Sets distance at which the entity starts fading. If <0, the entity will disappear instantly when end fade is hit. The value will scale appropriately if the entity is in a 3D Skybox.
fademaxdist
<float>- Sets distance at which the entity ends fading. If <0, the entity won't disappear at all. The value will scale appropriately if the entity is in a 3D Skybox.
SetModelScale
<vector> (only in)
- Multiplies the size of the model. Does not alter the physics collisions in most cases. Can take two values separated by a space, in which case the first value would be the target model scale and the second value would be the number of seconds the change in scale will be spread over. If there is no second value, the model will scale instantly.
Tip:The
modelscale
keyvalue can be AddOutputed as a workaround for other games with this input missing.

SetCycle
<float> (only in)
- Skip to a specific point in the current animation.
SetModel
<string> (only in)
- Changes the model to the specified path. Form of models/ammo/ammo_us.mdl.

SetPlayBackRate
<float> (only in)
- Change the animation speed multiplier.
Alpha
<integer>- Sets the entity's transparency to a number from 0 (invisible) to 255 (fully visible). Requires the entity to have its Render Mode (rendermode) set to a number other than 0.
AlternativeSorting
<boolean>- Swaps the rendering order of the entity. Used to attempt to fix sorting problems when rendering, for example an object rendering in front of translucent materials.
Color
<color255>- Sets an RGB color for the entity.
SetDamageFilter
<targetname>- Sets a filter for this entity for when it receives damage.
EnableDamageForces
- Allows the entity to be pushed by damage done to it (usually force amount correlates with the damage done).
DisableDamageForces
- Prevents the entity from being pushed by damage done to it.
Reflection:
DisableDrawInFastReflection
(in all games since)
- Turns off rendering of this entity in reflections when using
$reflectonlymarkedentities
in water material.
EnableDrawInFastReflection
(in all games since)
- Turn on rendering of this entity in reflections when using
$reflectonlymarkedentities
in water material.
Shadow:
DisableShadow
- Turn dynamic shadows off for this entity. Identical to applying
EF_NOSHADOW
.
EnableShadow
- Turn dynamic shadows on for this entity.
DisableReceivingFlashlight
(in all games since)
- This object will not receive light or shadows from projected textures.
Base:
AddContext
<string>- Adds to the entity's list of response contexts. See Context.
AddOutput
<string>- Assigns a new keyvalue/output on this entity. For keyvalues, some rely on extra necessary code to be ran and won't work if its simply just changed through this input. There is a strict format that must be followed:
// Format of changing KeyValues: "AddOutput [key] [value]"
//// Raw text:
"OnUser1" "!self,AddOutput,targetname new_name"
// Format of adding an Output: "AddOutput {targetname}:{inputname}:{parameter}:{delay}:{max times to fire, -1 means infinite}"
//// Raw text:
"OnUser1" "!self,AddOutput,OnUser1:SetParent:!activator:0.0:-1"
// Arguments can be left blank, but the empty blank should still be contained.
//// Raw text:
"OnUser1" "!self,AddOutput,OnUser1:ClearParent::0.0:-1"
|
ClearContext
- Removes all contexts from this entity's list.
ClearParent
- Removes this entity from the the movement hierarchy, leaving it free to move independently.
FireUser1
toFireUser4
- Fires the respective
OnUser
outputs; see User Inputs and Outputs.
Kill
- Removes this entity and any entities parented to it from the world.
KillHierarchy
- Functions the same as
Kill
, although this entity and any entities parented to it are killed on the same frame, being marginally faster thanKill
input.
RemoveContext
<string>- Remove a context from this entity's list. The name should match the key of an existing context.
SetParent
<string>- Move with this entity. See Entity Hierarchy (parenting).
SetParentAttachment
<string>- Change this entity to attach to a specific attachment point on its parent. The entity will teleport so that the position of its root bone matches that of the attachment. Entities must be parented before being sent this input.
SetParentAttachmentMaintainOffset
<string>- As above, but without teleporting. The entity retains its position relative to the attachment at the time of the input being received.
Outputs
OnLaunched
<targetname>- Fired when the canister is launched. This output automatically puts the targetname of the canister into the parameter box for inputs, if the mapper does not override the parameter with something else.
OnImpacted
- Fires when canister hits the ground.
OnOpened
- Fires when canister has finished opening.
Model:
OnIgnite
!FGD- Fired when the entity catches fire, such as from an
env_entity_igniter
or theIgnite
inputs.
Base:
OnUser1
toOnUser4
- These outputs each fire in response to the firing of the like-numbered
FireUser1
toFireUser4
Input; see User Inputs and Outputs.