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Use volume fog to shade the density of a volume shape.

This node is MP safe

Node nameParentsClassificationMFn typeCompatible function sets
volumeFogdependNode
shader/volume/fogkVolumeFogkBase
kNamedObject
kDependencyNode
kVolumeFog

Attributes (84)

The following quick index only shows top-level attributes (too many attributes to show them all): axialDropoff, color (3), colorRamp (6), colorRampInput, density, densityMode, dropoffMethod, dropoffShape, dropoffSubtract, edgeDropoff, farPointObj (3), farPointWorld (3), glowIntensity, illuminated, incandescence (3), lightDataArray (14), lightScatter, matrixWorldToEye, matteOpacity, matteOpacityMode, outColor (3), outGlowColor (3), outMatteOpacity (3), outTransparency (3), pointObj (3), pointWorld (3), rayDirection (3), transparency (3)

Long name (short name)TypeDefaultFlags
rayDirection (rad) float3outputinputconnectablehidden
The ray direction.
rayDirectionX (rdx) float0.0outputinputconnectablehidden
The x component of the direction.
rayDirectionY (rdy) float0.0outputinputconnectablehidden
The y component of the direction.
rayDirectionZ (rdz) float1.0outputinputconnectablehidden
The z component of the direction.
pointWorld (pw) float30.0, 0.0, 0.0outputinputconnectablehidden
The current start point of the volume interval
pointWorldX (pwx) float0.0outputinputconnectablehidden
The x component of the current sample position
pointWorldY (pwy) float0.0outputinputconnectablehidden
The y component of the current sample position
pointWorldZ (pwz) float0.0outputinputconnectablehidden
The z component of the current sample position
farPointWorld (fw) float31.0, 1.0, 1.0outputinputconnectablehidden
The end of the volume interval in world space.
farPointWorldX (fwx) float0.0outputinputconnectablehidden
The x-component of the world far-position.
farPointWorldY (fwy) float0.0outputinputconnectablehidden
The y-component of the world far-position.
farPointWorldZ (fwz) float0.0outputinputconnectablehidden
The z-component of the world far-position.
pointObj (po) float30.0, 0.0, 0.0outputinputconnectablehidden
The current start point of the volume interval in object space
pointObjX (pox) float0.0outputinputconnectablehidden
The x component of the current sample position
pointObjY (poy) float0.0outputinputconnectablehidden
The y component of the current sample position
pointObjZ (poz) float0.0outputinputconnectablehidden
The z component of the current sample position
farPointObj (fo) float31.0, 1.0, 1.0outputinputconnectablehidden
The end of the volume interval in world space.
farPointObjectX (fox) float0.0outputinputconnectablehidden
The x-component of the object space far-position.
farPointObjectY (foy) float0.0outputinputconnectablehidden
The y-component of the object space far-position.
farPointObjectZ (foz) float0.0outputinputconnectablehidden
The z-component of the object space far-position.
matrixWorldToEye (wte) fltMatrixidentityinputconnectable
The matrix that takes world space to eye space
lightDataArray (ltd) lightDataNULLarrayinputconnectablehidden
The lighting information this node computes.
lightDirection (ld) float3inputconnectablehidden
The light direction.
lightDirectionX (ldx) float1.0inputconnectablekeyablehidden
The x component of the direction.
lightDirectionY (ldy) float1.0inputconnectablekeyablehidden
The y component of the direction.
lightDirectionZ (ldz) float1.0inputconnectablekeyablehidden
The z component of the direction.
lightIntensity (li) float3inputconnectablehidden
The light intensity (it is a color).
lightIntensityR (lir) float1.0inputconnectablekeyablehidden
light intensity red value
lightIntensityG (lig) float1.0inputconnectablekeyablehidden
light intensity green value
lightIntensityB (lib) float1.0inputconnectablekeyablehidden
light intensity blue value
lightAmbient (la) booltrueinputconnectablekeyablehidden
The boolean that indicates if the light has an ambient component.
lightDiffuse (ldf) booltrueinputconnectablekeyablehidden
The boolean that indicates if the light has a diffuse component.
lightSpecular (ls) boolfalseinputconnectablekeyablehidden
The boolean that indicates if the light has a specular component.
lightShadowFraction (lsf) float0.0inputconnectablehidden
The visibility fraction to the light. value is in [0,1]
preShadowIntensity (psi) float0.0inputconnectablehidden
The light intensity without taking shadow into account.
lightBlindData (lbd) addr0inputconnectablehidden
The light blind data.
color (cl) float3outputinputconnectablestorable
Color is the basic color of the volume(when not otherwise defined).
colorR (cr) float0.9outputinputconnectablestorablekeyable
color red value
colorG (cg) float0.9outputinputconnectablestorablekeyable
color green value
colorB (cb) float0.9outputinputconnectablestorablekeyable
color blue value
colorRampInput (cri) enum0outputinputconnectablestorable
This determines the input to the color ramp. If transparency is used, then the value used from the colorRamp is relative to the current transparency within the volume. More transparent regions will use the color at the left of the ramp and totally opaque regions will have the color at the right. For concentric mapping the distance to the volume center determines color from the ramp. Y Gradient selects the color based on the position along the y axis. If Ignore is set then the color parameter is used instead of the color ramp.
colorRamp (crm) compoundn/aarrayoutputinputconnectablestorablekeyable
This defines the color ramp used by the colorRampInput, which defines a mapping of this ramp to the volume.
colorRamp_Position (crmp) float0.0outputinputconnectablestorablekeyable
Position of ramp value on normalized 0-1 scale
colorRamp_Color (crmc) float3outputinputconnectablestorablekeyable
Ramp color at the sibling position
colorRamp_ColorR (crmcr) float0.0outputinputconnectablestorablekeyable
Ramp red channel value at the sibling position
colorRamp_ColorG (crmcg) float0.0outputinputconnectablestorablekeyable
Ramp green channel value at the sibling position
colorRamp_ColorB (crmcb) float0.0outputinputconnectablestorablekeyable
Ramp blue channel value at the sibling position
colorRamp_Interp (crmi) enum0outputinputconnectablestorablekeyable
Ramp Interpolation controls the way the intermediate values are calculated. The values are:
    None: No interpolation is done; the different colors just show up as different bands in the final texture.

    Linear: The values are interpolated linearly in RGB color space.

    Smooth: The values are interpolated along a bell curve, so that each color on the ramp dominates the region around it, then blends quickly to the next color.

    Spline: The values are interpolated with a spline curve, taking neighboring indices into account for greater smoothness.

transparency (t) float3outputinputconnectablestorable
Transparency is the color transparency of the volume
transparencyR (tr) float0.5outputinputconnectablestorablekeyable
transparency red value
transparencyG (tg) float0.5outputinputconnectablestorablekeyable
transparency green value
transparencyB (tb) float0.5outputinputconnectablestorablekeyable
transparency blue value
incandescence (ic) float3outputinputconnectablestorable
Incandescence makes a material appear opalescent, as if it were emmitting light itself, such as lava or a phosphorescent moss. A slight touch of incandescence on vegetable matter, for example, can make the vegetation look alive.

By default, the color is black, which has no effect on the surface.

Note: although incandescence makes a surface appear to glow, it does not actually act as a source of light in the scene.

See also Glow Intensity.

incandescenceR (ir) float0.0outputinputconnectablestorablekeyable
incandescence red value
incandescenceG (ig) float0.0outputinputconnectablestorablekeyable
incandescence green value
incandescenceB (ib) float0.0outputinputconnectablestorablekeyable
incandescence blue value
glowIntensity (gi) float0.0outputinputconnectablestorablekeyable
Glow Intensity is 0 by default, meaning that no glow is added to the material. As this is turned up, the material seems to 'glow' with a faint halo of light around it.

Note that this is different from the Incandescence attribute in a few important ways. First, glow is added as a post-process at the end of rendering. (Incandescence just makes the surface appear brighter.) Second, glow adds a halo, which incandescence does not.

outGlowColor (ogc) float3outputconnectable
Out Glow Color is the final output glow color from this node (if this node is glowing)
outGlowColorR (ogr) float0.0outputconnectable
out glow color red value
outGlowColorG (ogg) float0.0outputconnectable
out glow color green value
outGlowColorB (ogb) float0.0outputconnectable
out glow color blue value
density (dns) float1outputinputconnectablestorablekeyable
the density or opacity of the fog
densityMode (dmd) enum1outputinputconnectablestorable
Determines if the density is defined in worldspace or objectspace. Objectspace density preserves the look when an object is scaled.
dropoffShape (dos) enum0outputinputconnectablestorable
Defines a shape to use to define an outer boundary for creating a soft edged volume. If one is rendering a box volume then Cube should match the edges of the volume. Likewise for Sphere and Cone volumes. LightCone is different from Cone in that the fade does not occur near the point of the cone.
edgeDropoff (edr) float.5outputinputconnectablestorablekeyable
Defines the rate at which the density drops off towards the edge defined by the Dropoff Shape.
axialDropoff (axd) float0.3outputinputconnectablestorablekeyable
Defines how quickly the density drops off down the axis of a cone.
dropoffMethod (drm) enum0outputinputconnectablestorable
Defines the the way the edge dropoff is performed Scale Opacity multiplies the overall density by the dropoff value, causing a uniform change in transparency. Subtract Density subtracts the dropoff value multiplied by the Dropoff Subtract value from the density. This is primarily useful when the density or transparency is textured. Low density regions will become completely transparent, while high density regions will not be affected much. This can help preserve the character of a pluffy cloud, for example.
dropoffSubtract (drs) float1.0outputinputconnectablestorablekeyable
This is the maximum amount of density subtracted from the volume when Dropoff Method = Subtract Density. If the volume density is 1.0 and Dropoff Subtract is 1.0 then the edge of the volume will be completely transparent.
illuminated (il) boolfalseoutputinputconnectablestorable
If Illuminated is turned on then lights will be computed for the fog. The lighting happens for each volume span as determined by the volume samples parameter on the geometry.
lightScatter (lsc) float1.0outputinputconnectablestorablekeyable
This is the amount that the fog scatters light in all directions. As it approaches zero the fog tends to scatter light more and more in a directional fashion, resulting in halos around light sources.
matteOpacityMode (mom) enum2outputinputconnectablestorable
Matte Opacity Mode controls how the system will use the Matte Opacity attribute (below). When you are rendering with a matte (i.e. an alpha channel, or mask), these two attributes are used to control how this material will show up in the matte. This is useful if you will be compositing your rendered images later on.

There are three settings, used for different purposes:

    Opacity Gain: (the default). Matte values are calculated in the normal way (based on the transparency of the object) then multiplied by the Matte Opacity. (Matte Opacity has a default value of one, by default these attributes have no effect.) With Opacity Gain, you can animate the Matte Opacity value to change the overall transparency of the object when it is later composited.

    Solid Matte: This is like Opacity Gain, except that the normally-calculated matte values are ignored in favor of the Matte Opacity setting. The entire matte for the object is set to the value of the Matte Opacity attribute. If there are transparent areas on the object, their transparency is ignored in the matte. Use this setting to composite an object with transparent parts, when you do not want the background to show through them.

    Black Hole: The value of Matte Opacity is ignored, and all the matte for this material is set to be transparent. Use this when you are creating substitute geometry in a scene, which is standing in for objects in a background image that you will be compositing with later. Your stand-in objects will 'punch a hole' in the matte. This allows other computer-generated geometry to pass behind your stand-in objects. Later, when foreground and background are composited, the results will be correct, with the background object showing through the 'black hole' areas.

matteOpacity (mog) float1.0outputinputconnectablestorablekeyable
Matte Opacity is used (along with Matte Opactiy Mode) to affect how the matte (i.e. alpha channel or mask) for this material will be calculated. See Matte Opacity Mode above for full details.
outColor (oc) float30.0, 0.0, 0.0outputconnectable
Out Color. Connect another attribute to this to control the color of the volume shader.
outColorR (ocr) float0.0outputconnectable
Out Color red value
outColorG (ocg) float0.0outputconnectable
Out Color green value
outColorB (ocb) float0.0outputconnectable
Out Color blue value
outTransparency (ot) float30.0, 0.0, 0.0outputconnectable
Out Transparency. Connect another attribute to this to control the Shader's transparency. Higher values (that is, brighter colors) make the object more transparent; darker colors make it more opaque.
outTransparencyR (otr) float0.0outputconnectable
Out Transparency red value
outTransparencyG (otg) float0.0outputconnectable
Out Transparency green value
outTransparencyB (otb) float0.0outputconnectable
Out Transparency blue value
outMatteOpacity (omo) float31.0, 1.0, 1.0outputconnectable
Out Matte Opacity. Connect another attribute to this to control the opacity of the material's matte (alpha) channel.
outMatteOpacityR (omor) float0.0outputconnectable
Out Matte Opacity red value
outMatteOpacityG (omog) float0.0outputconnectable
Out Matte Opacity green value
outMatteOpacityB (omob) float0.0outputconnectable
Out Matte Opacity blue value