# `func_rotating`

`func_rotating` is a brush entity available in all games.

Note: This entity did not rotate visually until the 19/12/2018 patch, due to bugged implementation of the `Client-side rotation` spawnflag.
Bug:Always fire the `Stop` input on this entity before killing it, otherwise looping sounds may continue playing forever!
Bug:The maximum degrees this angle can turn is 360000 degrees, at which it stops rotating.
Fix: This can be remedied by scripting the entity to pause rotating for a short period of time.

## Entity Description

A visual guide showing the axis in each viewport (Click to enlarge)

It is used to create rotating brushes. Compare with `func_door_rotating`.

### Friction Explanation & Formula

Fan friction may be a little tricky to understand. Below is an explanation of how it works.

If Hammer has the fanfriction key set to 0 and the game spawns the entity, code sets it to 1 so it doesn't divide by zero.

Friction = fanfriction key / 100

Key Hammer Value Code Value
fanfriction 100 1
fanfriction 50 0.5
fanfriction 0/1 0.01

Note: These formulas get called every 0.1 seconds.

Purpose: Think function: Accelerates a `func_rotating` to a higher angular velocity.

```new_speed = fabs( current_speed ) + 0.2 * maxspeed * fanfriction;
```

Purpose: Decelerates the rotator from a higher speed to a lower one.

```new_speed = fabs( current_speed ) - 0.1 * maxspeed * fanfriction;
```

Conclusion:

• A higher `fanfriction` value will accelerate/deaccelerate faster.
• A lower `fanfriction` value will accelerate/deaccelerate slower.

## Keyvalues

Max Rotation Speed `(maxspeed)` <integer>
The maximum rotation speed of the brushes, in degrees per second. Seems to be limited to a number around 2000, after which the rotational speed ignores the last remaining digits (e.g., 2500=250).
Friction (0 - 100%) `(fanfriction)` <integer>
The amount of rotational friction. Value must be between 0 and 100 %. The lower the friction is, the slower it spins up and spins down. This is the opposite of how it would work in real life.
Rotating sound WAV `(message)` <sound>
Sound to play while rotating.
Bug:Always fire the `Stop` input on this entity before killing it, otherwise looping sounds may continue playing forever!
Volume (10 = loudest) `(volume)` <integer>
The volume of the rotation sound.
Minimum Light Level `(_minlight)` <string>
The minimum level of ambient light that hits this brush.
Blocking Damage `(dmg)` <integer>
Damage done to any entity that blocks the rotation, per frame.
Solid Type `(solidbsp)` <choices>
Brush solidity type
• 0 : VPhysics
• 1 : BSP

Base:
Brush Model `(model)` <string> !FGD
Which bmodel to display.
Collisions `(solid)` <choices>
Method of collision for this entity.

Values:

• 0: None
• 1: BSP (QPhysics) !FGD
Bug:In , if an entity using QPhysics collisions is hit by Gel, the game will crash!
• 2: Bounding Box
• 3: Oriented Bounding Box (Use for runtime spawned brush entities meant to be rotated) !FGD
• 4: Oriented Bounding Box but constrained to Yaw only !FGD
• 5: Custom/Test (Usually no collision with anything) !FGD
• 6: VPhysics

Name `(targetname)` <string>
The name that other entities use to refer to this entity.
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.
Tip:Changing this on runtime still has use, like making matching an entry in S_PreserveEnts will persist the entity on new rounds!
Spawnflags `(spawnflags)` <flags> !FGD
Toggles exclusive features of an entity, its specific number is determined by the combination of flags added.
Effects `(effects)` <flags> !FGD
Combination of effect flags to use.
Entity Scripts `(vscripts)` <scriptlist> (in all games since ) (also in )
Space delimited list of VScript files (without file extension) that are executed after all entities have spawned. The scripts are all executed in the same script scope, later ones overwriting any identical variables and functions. Scripts executed on the worldspawn entity will be placed in root scope.
Think function `(thinkfunction)` <string> (in all games since ) (also in )
Name of the function within this entity's script that'll be called automatically every 100 milliseconds, or a user-defined interval if the function returns a number. Avoid expensive operations in this function, as it may cause performance problems.
Lag Compensation `(LagCompensate)` <boolean> (in all games since ) !FGD
Set to Yes to lag compensate this entity. Should be used very sparingly!
Is Automatic-Aim Target `(is_autoaim_target)` <boolean> (in all games since ) !FGD
If set to 1, this entity will slow down aiming movement for consoles and joystick controllers when the entity is under the crosshairs.

Minimum Light Level `(_minlight)` <normal>
Minimum amount of light to hit this brush (monochromatic). Values over 1 are overbright, and will bloom in HDR mode.
Shadows `(vrad_brush_cast_shadows)` <boolean> (in all games since )
Determines if this entity will cast lightmap shadows.

VisibleBrush:

Render Mode `(rendermode)` <choices>
Set a non-standard rendering mode on this entity.
 0: Normal 1: Color 2: Texture 3: Glow 4: Solid/Alphatest 5: Additive 6: Removed, does nothing 7: Additive Fractional Frame 8: Alpha Add 9: World Space Glow 10: Don't Render
Render FX `(renderfx)` <choices>
Various somewhat legacy alpha effects.
 Bug:Alpha effects from 0 to 10 are unavailable due to the bug in code in 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/(in all games since ) Fades in over 1 s) 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)/(in all games since ) Fade Out (instant; not very useful outside of code) 16: Hologram (Distort + "distance fade")/(in all games since ) Fade In (instant; not very useful outside of code) 17: Scale Up ("Explode"/"scale up really big!" causes wild stretching of model parts) (in )/Fade Wider Pulse (varies alpha by ±255 over a period over a period of 0.26 s) (in all games since ) 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 (removed since ) (not in ) Todo: what does this do? may be nonfunctional
Render FX / Transparency (0–255) `(renderamt)` <integer 0–255>
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.
Texture Frame `(texframeindex)` <integer> !FGD
The frame number for any animated textures on this entity.

Disable Shadows `(disableshadows)` <boolean>
Prevents the entity from creating cheap render-to-texture shadows, or lightmap shadows if the entity is a `prop_static`. Does not affect shadow mapping.
Disable Receiving Shadows `(disablereceiveshadows)` <boolean>
Prevent the entity from receiving dynamic shadows on itself.
Shadow Cast Distance `(shadowcastdist)` <integer> !FGD
Sets how far the entity casts dynamic shadows. 0 means default distance from the `shadow_control` entity.
Disable ShadowDepth `(disableshadowdepth)` <boolean> (in all games since )
Used to disable rendering into shadow depth (for projected textures) for this entity.
Disable flashlight `(disableflashlight)` <boolean> (in all games since )
Used to disable projected texture lighting and shadows on this entity.
Projected Texture Cache `(shadowdepthnocache)` <choices> (in all games since )
Used to hint projected texture system whether it is sufficient to cache shadow volume of this entity or to force render it every frame instead.
 0 : Default 1 : No cache - render every frame 2 : Cache it - render only once

SystemLevelChoice:

Minimum / Maximum Effect Details Level `(mincpulevel / maxcpulevel)` <choices> (in all games since )
Don't render for players with Effect Details levels that exceed the minimum or maximum.[Key names are related to `cpu_level` cvar used by Effect Details.]
 0: Default ("Low" for`mincpulevel`, "High" for`maxcpulevel`) 1: Low 2: Medium 3: High
Minimum / Maximum Shader Details Level `(mingpulevel / maxgpulevel)` <choices> (in all games since )
Don't render for players with Shader Details levels that exceed the minimum or maximum.[Key names are related to `gpu_level` cvar used by Shader Details.]
 0: Default ("Low" for`mingpulevel`, "Very High" for`maxgpulevel`) 1: Low 2: Medium 3: High 4: Very High

DXLevelChoice:

Minimum / Maximum DX Level `(mindxlevel / maxdxlevel)` <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. 0 - Default (no bounding) 60 - DirectX 6 (!FGD for mindxlevel) 70 - DirectX 7 80 - DirectX 8 (Geforce4 Ti 4600) 81 - DirectX 8.1 (GeForce FX 5200) 90 - DirectX 9 Shader Model 2 92 - OpenGL equivalent to DirectX 9 Shader Model 2 (using ToGL; only) !FGD 95 - DirectX 9 Shader Model 3 and DXVK 98 - DX9Ex ( only) !FGD

Reflection:
Render in Fast Reflections `(drawinfastreflection)` <boolean> (in all games since )
If enabled, this entity will render in fast water reflections (i.e. when a water material specifies `\$reflectonlymarkedentities`) and in the world impostor pass.

## Flags

•  [`1`] : Start ON
•  [`2`] : Reverse Direction
•  [`4`] : X Axis
If enabled, the entity will spin at the X Axis.
•  [`8`] : Y Axis
If enabled, the entity spin at the Y Axis.
•  [`16`] : Acc/Dcc
If enabled, the entity will accelerate and decelerate from maximum speed based on the Friction property.
•  [`16`] : Client-side Rotation (only in )
Intended to simulate the entity entirely on the client.
•  [`32`] : Fan Pain
With this enabled, the player will be hurt when coming into contact with the brush.
•  [`64`] : Not Solid
•  [`128`] : Small Sound Radius
Use ATTN_IDLE (60dB).
•  [`256`] : Medium Sound Radius
Use ATTN_STATIC (~67dB).
•  [`512`] : Large Sound Radius
Use ATTN_NORM (~75dB). If the other two options are unset, this is used.
•  [`1024`] : Client-side Animation (in all games since )

## Inputs

`SetSpeed` <float>
Set the speed as a ratio of the specified Max Rotation Speed, where 0 is stopped and 1 is the Max Rotation Speed. Negative values rotate backwards.
`Start`
Start the rotator rotating.
`Stop`
Stop the rotator from rotating.
`StopAtStartPos`
`Stop` the rotator from rotating when it gets around to the start position again (on its rotation axis). If the speed is greater than 100 degrees per second, slows down to 100 degrees per second and spins for one extra revolution before stopping.
`StartForward`
Start the rotator rotating forward at maximum speed.
`StartBackward`
Start the rotator rotating backward at maximum speed.
`Toggle`
Toggle the rotator between rotating and not rotating.
`Reverse`
Reverse the direction of rotation of the rotator, preserving the current speed.
`SnapToStartPos`  (in all games since )
Snap to the initial position and stop moving.
`GetSpeed`  (in all games since )
Causes the `func_rotating` to fire its `OnGetSpeed` output with its current speed.

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` to `FireUser4`
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 than`Kill`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.
`Use`  !FGD
Same as a player invoking +use; no effect in most cases.
`DispatchResponse` <string> !FGD
Dispatches a response to the entity. See Response and Concept.
`DispatchEffect` <string> (removed since ) !FGD
Dispatches a special effect from the entity's origin; See also List of Client Effects. Replaced by the particle system since .
`RunScriptFile` <script> (in all games since ) (also in )
Execute a VScript file from disk, without file extension. The script contents are merged with the script scope of the receiving entity.
`RunScriptCode` <string> (in all games since ) (also in )
Execute a string of VScript source code in the scope of the entity receiving the input. String quotation may be needed when fired via console.
Bug:In Hammer, using string arguments will corrupt the VMF file's structure, making the file unviewable for the next Hammer session.
Fix:Remove the string argument manually with a text editor.
Note: Backtick characters ` are replaced with quotation marks at runtime, allowing quotation marks to be used when normally not possible.
`CallScriptFunction` <string> (in all games since ) (also in ) !FGD
Calls a VScript function defined in the scope of the receiving entity.
`TerminateScriptScope`  (only in ) !FGD
Destroys the script scope of the receving entity.
`SetLocalOrigin` <coordinates> (in all games since ) !FGD
Send this entity to a spot in the map. If the entity is parented to something, it will be offset from the parent by this amount.
`SetLocalAngles` <angles> (in all games since ) !FGD
Set this entity's angles.

Visible Brush:
`Alpha` <integer 0–255>
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.
`EnableDraw`  (in all games since )
Removes `EF_NODRAW` from the entity.
`DisableDraw`  (in all games since )
Applies `EF_NODRAW` to the entity. Note that this is different from `rendermode 10`.
`EnableReceivingFlashlight`  (in all games since )
Makes it so that the entity is lit by `env_projectedtexture`s.
`DisableReceivingFlashlight`  (in all games since )
Prevents the entity from being lit by `env_projectedtexture`s. The shadow made by the texture will still cast.

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.

`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 )
`EnableReceivingFlashlight`  (in all games since )

## Outputs

`OnGetSpeed` <integer> (in all games since )
Fired when the `GetSpeed` input is called. The current speed of the `func_rotating` is passed with this output.

Targetname:
`OnUser1` to `OnUser4`
These outputs each fire in response to the firing of the like-numbered `FireUser1` to `FireUser4` Input; see User Inputs and Outputs.
`OnKilled`  (only in )
This output fires when the entity is killed and removed from the game.

• `func_door_rotating`
• `func_platrot`
• `func_rot_button`
• `momentary_rot_button`