Func precipitation

Template:Base brush It creates rain, snow, or ash inside its volume.

Rain Related Console Commands

There are a number of console commands that control func_precipitation rendering.

• See also Precipitation issues - details various issues and workarounds involving the use of this entity.

Command Name	Value	Description
r_RainParticleDensity	<float>	Set the density to enable or disable any precipitation particle. Value 1 to enable and 0 to disable. Todo: Appears to be invalid. Which Source game(s) feature this specific command?
r_rainalpha	<float>	Adjusts transparency of rain particles.
r_rainProfile	<bool>	Displays stats on rain rendering costs.
r_RainHack	<bool>	Overrides density values set in Hammer. Enabling will result in longer and more dense rain than at 100%. Can help solve visibility issues. Note:Rain may fall through brushes when this command is enabled.
r_rainspeed	<float>	Lower values will cause rain to disappear sooner and fall slower. Default value is 600.0f
r_RainSideVel	<float>	Controls sideways movement of the rain particles.
r_RainSimulate	<bool>	Toggles animation on the rain; freezes the rain when set to 0.
r_rainwidth	<float>	Widens the rain's alpha to desired value. Default value is 0.5
r_RainRadius	<float>	Distance from the brush where the rain starts/stops rendering.
r_rainlength	<float>	Changes the length of the rain particles. Default value is 0.1f
r_RainSplashPercentage	<float>	Percent chance of splash particles spawning when a particle is used.
r_raindensity	<float>	Bug:Appears to have no effect. Deprecated?  [todo tested in ?] Tip:Use r_RainParticleDensity instead.
r_rainalphapow	<float>	Bug:Appears to have no effect. Deprecated?   [todo tested in ?]

Todo: The names of these seem descriptive enough for most of them, but what does r_raindensity, and r_rainalphapow do?

Warning:Precipitation volumes shouldn't be placed in the same volume as func_smokevolume is. Otherwise engine may freeze at the end of loading the level. It is probably caused by some particle coding that do not accept this two types of sprites to render at once (in the same volume).

Keyvalues

Density (0-100%) ([todo internal name (i)]) <integer>

This is the amount of particles that fall down from top side of brush. However distance from first particle to second depends on a brush volume size!

Color (R G B) ([todo internal name (i)]) <color255>

Color added to sprites which are rendered transparently (probably rain and snow particles)

Precipitation Type ([todo internal name (i)]) <choices>

Precipitation type

Value	Description	Description/Notes
0	Rain	Rain falling. The only official instance of this effect in use is found in the CS:S map "de_aztec".
1	Snow	Identical to rain, Use "Snowfall" instead.
2	Ash	Used to great extent in EP1. Appears with missing textures in most games other than EP1. Can be fixed by extracting materials/effects/fleck_ash1 to 3 VMTs and VTFs, and ember_swirling001.vtf from ep1_pak_dir.vpk. This issue is fixed in EP1 and onwards.
3	Snowfall	Snow falling. Used in the DoD:S map "dod_colmar".
4	Particle Rain	Template:L4D add Particle rain with slight refraction. Used in Left 4 Dead's "No Mercy" campaign and the CS:GO map "de_aztec".
5	Particle Ash	Template:L4D add Particle ash with orange tint. Used in Left 4 Dead's "Dead Air" campaign.
6	Particle Rain Storm	Template:L4D2 add Particle rain with higher density of streaks and impact particles. Used in Left 4 Dead 2's "Hard Rain" and "The Passing" campaigns.
7	Particle Snow	Template:CSGO add Particle snowfall. Used in the CS:GO map "ar_monastery".
8	Particle Bugs	Template:L4D2 add Particle flying bugs. Used in Left 4 Dead 2's "Swamp Fever" campaign.
9	Particle Smoke	Template:L4D2 add Particle smoke with view-obscuring density. Used in Left 4 Dead 2's "Dead Center" campaign.

Name (targetname) <string>[ Edit ]

The name that other entities refer to this entity by, via Inputs/Outputs or other keyvalues (e.g. parentname or target).
Also displayed in Hammer's 2D views and Entity Report.

See also:  Generic Keyvalues, Inputs and Outputs available to all entities

Parentname:

Parent (parentname) <targetname>

Specifies a movement parent. An entity will maintain its initial offset from its parent. An attachment point can be added to the end of the name, separated by a comma.

Inputs

Alpha

Unlisted input. Changes the density of the rain, and may add additional particle effects like fog or leafs. It accepts inputs from -1 to 255.

Parentname:

SetParent <stringRedirectInput/string>

Move with this entity. See Entity Hierarchy (parenting).

SetParentAttachment <stringRedirectInput/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 <stringRedirectInput/string>

As above, but without teleporting. The entity retains its position relative to the attachment at the time of the input being received.

ClearParent

Removes this entity from the the movement hierarchy, leaving it free to move independently.