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| Since | 14.5 |
Overview ¶
This shader can be used to create realistic renders of smoke, fire and explosion simulations or procedurally generated volumes. It is used by many of the tools on the Pyro FX shelf.
This shader relies on a set of volumes to do it’s work. Their names are set on the Smoke Field, Fire Intensity Field and Fire Temperature Field tabs. These also provide additional, fine-grained control over each a volume.
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The Smoke Field provides the smoke density.
-
The Fire Intensity Field controls the intensity of light emitted by the fire.
-
The Fire Temperature Field is converted to the fire’s color.
Note
This is a SHOP shader, which means it cannot be layered with other shaders.
If you need to do this, or if you need more control, you can use 
Pyro Core Shader VOP which this shader is based on.
Parameters ¶
General ¶
Provides a simple, compact interface for defining the overall look.
Smoke ¶
Density Scale
Controls the overall density. This is multiplied with the Smoke Field's value.
The figure below shows the effect of a relative change by various factors:
Smoke Brightness
Controls the overall smoke brightness. This is multiplied with the Smoke Color and the Cd volume, if Tint Smoke Color with Cd is enabled.
The figure below shows the effect of a relative change by various factors:
Smoke Color
Controls the overall smoke color.
Tint Smoke Color with Cd
Tint the smoke’s color using a color volume.
This can either be a set of 3 volumes named Cd.x, Cd.y and Cd.z or a single VDB Vector Volume named Cd.
Scattering Phase
Controls the direction in which light entering the volume is scattered. At the default of 0, light scatters evenly in all directions (isotropic scattering). Positive values up to 1 scatter more and more in the same direction as the incoming light, Negative values down to -1 scatter backwards.
In reality, this effect depends on type of particles suspended in the volume.
The figure below shows the effect of various values on smoke lit from behind by a green light:
Fire ¶
Intensity Scale
Scales the fire’s emission intensity. This is multiplied with Fire Intensity Field's value
The figure below shows the effect of a relative change by various factors:
Temperature Scale
Scales the fire’s temperature. This is multiplied with Fire Temperature Field's value.
The fire’s color depends on it’s temperature.
The figure below shows the effect of a relative change by various factors:
Temp>Color Mapping
The method to use for mapping temperature to a color.
Constant
Ignore temperature and set a global color.
Ramp
Map temperature to color using a color ramp.
Physical (Black-Body)
Converts physical color temperatures to RGB color values and intensities, with some additional artistic controls.
Constant Color
Sets the fire color uniformly, ignoring temperature. #id: fc_constantcolor
Input Range
Sets the range of temperatures that map to the ramp.
Ramp
The colors within the Input Range are mapped to the colors set on this ramp.
Color Temp in Kelvin
This sets the color temperature correpsonding to a temperature field value of 1.0.
Adaptation
Manipulates the low end of the generated intensity.
Burn
Manipulates the high end of the generated intensity.
Shadows ¶
Shadow Density
Controls the overall density of shadow’s cast by the smoke.
The figure below shows the of effect various values:
Shadow Color
The color of shadows cast by the smoke.
Filtering ¶
Filter
The type of filter to use for field shape controls and noise.
Point
Takes a single sample, no filtering.
Box
Applies a box filter.
Gaussian
Applies a gaussian filter. Produces the smoothest results.
Scale
A scale on the width of the filter.
Smoke Field ¶
The controls on this tab allow you to change the look of the Smoke Field. The operations are performed in the order they're listed in.
Density Volume
The name of the smoke density volume to be rendered.
Shape ¶
Fit to Range (Unclamped)
Maps a range of input values to a different output range.
Source Range
The range of input values.
Target Range
The range of output values.
Use Lookup Ramp
Maps input values to the ramp values, giving find-grained control over the shape of the field.
Use Fit to Range to controls which range of values is used to look up the ramp.
Ramp Boundaries
How to compute the result for inputs below/above the ramp’s range.
Hold
Returns the value at the nearest end of the ramp (for example, if the
ramp’s range is 0-1, and the input is -10, it will return the
ramp value for 0).
Cycle
Repeats the ramp continuously outside the range.
Cycle-Accumulate
Like “Cycle”, but starts each cycle relative to the end value of the previous cycle.
Mirror
Cycles before/after the range are mirror images (reversed) of one another. The first cycle is not mirrored.
Slope
Extends a line using the slope at the beginning/end of the ramp range.
Ramp
The lookup ramp.
Contour
Increases or decreases contrast for values at the bottom of the input range. This is sometimes useful to control feathering in volume fields.
Soft Clip
Increases or decreases contrast for values at the top of the input range. This is sometimes useful to control feathering in volume fields.
Clamp at Lower Limit
Clamp values to a lower limit.
Clamp at Upper Limit
Clamp values to an upper limit.
Final Scale
A multiplier on the final value.
Noise ¶
Enable
Whether to add any noise to this field.
Mode
Controls how the noise is applied to this field.
Offset (Field + Noise)
The noise value is added to the field value.
Scale (Field + Noise)
The field value is multiplied with the noise value.
Type
The type of noise to generate. Different algorithms give noise with different characteristics.
Fast
The default. A faster and more interesting variant of Perlin noise.
Frequency is scaled by 1.25.
Sparse Convolution
Sparse Convolution noise is similar to Worley noise. Does not have artifacts at grid points.
Frequency is scaled by 1.25.
Alligator
Produces a bumpy output. Named for its alleged resemblance to alligator skin.
Frequency is scaled by 1.64.
Perlin
A noise where the visual details are the same size. Wikipedia article
Perlin Flow
A noise that’s stable over time, like a rotated Perlin noise, useful to create noise that seems to swirl and flow smoothly across time. Use the Flow rotation parameter below to control the rotation.
Simplex
A noise similar to Perlin but the noise lattice is on a tetrahedral mesh rather than a grid. This can avoid the grid patterns often visible in Perlin noise.
Worley Cellular F1
Produces cellular features similar to plant cells, ocean waves, honeycombs, cratered landscapes, and so on. Wikipedia article
Worley Cellular F2-F1
A variant of Worley noise that produces blunted and cornered features.
Manhattan Cellular F1
A variant of Worley F1 noise that uses Manhattan distance calculation. Useful when you want unusual-looking noise.
Manhattan Cellular F2-F1
A variant of Worley F2-F1 noise that uses Manhattan distance calculation. Useful when you want unusual-looking noise.
Chebyshev Cellular F1
A variant of Worley F1 noise that uses Chebyshev distance calculation. Useful when you want unusual-looking noise.
Chebyshev Cellular F2-F1
A variant of Worley F2-F1 noise that uses Chebyshev distance calculation. Useful when you want unusual-looking noise.
Frequency
The frequency of the noise. Higher values give smaller scaled details in the noise.
Offset
The offset of the input into the noise function. If you visualize the noise as a 2D graph or 3D height field, this has the effect of “panning” across the space of possible noise outputs. If you have the general noise effect you want but just want to get a different set of values for a different look, try changing the offset.
Period
When Periodic is on, the multiple of the input range before the noise pattern repeats.
Note
If Lacunarity is not 2, successive octaves will not have matching periods so a periodic noise won’t be built.
Note
Some noise types have an implicit frequency scale that must be taken into account.
Fractal ¶
Fractal Type
None
Does not add any additional noise on top of the basic noise.
Standard
Adds pseudo-random noise on top of the basic output.
Terrain
Adds noise like “Standard” but dampens the noise in the valleys, which can be useful for generating mountainous terrain.
Hybrid
Like terrain, but with more sharpness in the valleys.
Max Octaves
The number of iterations of distortion to add to the output of the basic noise. The more iterations you add, the more “detailed” the output. Note that the output may have fewer octaves than this parameter (that is, increasing the parameter will eventually stop adding detail), because the node eventually stops when there’s no more room to add more detail in the output.
Lacunarity
The frequency increment between iterations of fractal noise added to the basic output. Note that you can use a negative value.
Roughness
The scale increment between iterations of fractal noise added to the basic output. The higher the value the larger the “jaggies” added to the output. You can use a negative value for roughness.
Warping ¶
Enable Lattice Warp
Adds “stringiness” or “wiriness” to standard noise.
Accumulate Lattice Warp
When Lattice Warp is on, this accumulates the warp for each iteration (octave) of added fractal noise. When used in images, this can add interesting smudgy effects, and interesting landmarks when used for terrain.
Freq
Enable Gradient Warp
Enables a slider to widen the peaks or valleys of the noise output.
Accumulate Gradient Warp
When Lattice Warp is on, this accumulates the warp for each iteration (octave) of added fractal noise. When used in images, this can add interesting smudgy effects, and interesting landmarks when used for terrain.
Flow Rotation
When Noise type is “Flow”, this controls the rotation of the “swirl”, from 0 to 1. Because this parameter is fractional, you can’t just use $F to animate it, since all integral values will look the same, representing a complete revolution. Instead, try something like $FF / 100.
Output Correction ¶
Bias
Enables the bias controls to nudge values up or down.
Gain
Enables the gain controls to increase or decrease the contrast.
Complement
Outputs the numerical complement (1 - x) of the computed noise. Basically turns the output upside-down.
Output Range (Clamped)
Enables the New minimum and New maximum parameters to allow you to map the noise, which is normally in the [0,1] range, to a different range of values.
Final Amplitude
Scales the final conditioned output up or down.
Fire Intensity Field ¶
The controls on this tab allow you to change the look of the Fire Intensity Field, which controls the fire’s emission intensity. The operations are performed in the order they're listed in.
Density Volume
The name of the smoke density volume to be rendered.
Shape ¶
Fit to Range (Unclamped)
Maps a range of input values to a different output range.
Source Range
The range of input values.
Target Range
The range of output values.
Use Lookup Ramp
Maps input values to the ramp values, giving find-grained control over the shape of the field.
Use Fit to Range to controls which range of values is used to look up the ramp.
Ramp Boundaries
How to compute the result for inputs below/above the ramp’s range.
Hold
Returns the value at the nearest end of the ramp (for example, if the
ramp’s range is 0-1, and the input is -10, it will return the
ramp value for 0).
Cycle
Repeats the ramp continuously outside the range.
Cycle-Accumulate
Like “Cycle”, but starts each cycle relative to the end value of the previous cycle.
Mirror
Cycles before/after the range are mirror images (reversed) of one another. The first cycle is not mirrored.
Slope
Extends a line using the slope at the beginning/end of the ramp range.
Ramp
The lookup ramp.
Contour
Increases or decreases contrast for values at the bottom of the input range. This is sometimes useful to control feathering in volume fields.
Soft Clip
Increases or decreases contrast for values at the top of the input range. This is sometimes useful to control feathering in volume fields.
Clamp at Lower Limit
Clamp values to a lower limit.
Clamp at Upper Limit
Clamp values to an upper limit.
Final Scale
A multiplier on the final value.
Noise ¶
Enable
Whether to add any noise to this field.
Mode
Controls how the noise is applied to this field.
Offset (Field + Noise)
The noise value is added to the field value.
Scale (Field + Noise)
The field value is multiplied with the noise value.
Type
The type of noise to generate. Different algorithms give noise with different characteristics.
Fast
The default. A faster and more interesting variant of Perlin noise.
Frequency is scaled by 1.25.
Sparse Convolution
Sparse Convolution noise is similar to Worley noise. Does not have artifacts at grid points.
Frequency is scaled by 1.25.
Alligator
Produces a bumpy output. Named for its alleged resemblance to alligator skin.
Frequency is scaled by 1.64.
Perlin
A noise where the visual details are the same size. Wikipedia article
Perlin Flow
A noise that’s stable over time, like a rotated Perlin noise, useful to create noise that seems to swirl and flow smoothly across time. Use the Flow rotation parameter below to control the rotation.
Simplex
A noise similar to Perlin but the noise lattice is on a tetrahedral mesh rather than a grid. This can avoid the grid patterns often visible in Perlin noise.
Worley Cellular F1
Produces cellular features similar to plant cells, ocean waves, honeycombs, cratered landscapes, and so on. Wikipedia article
Worley Cellular F2-F1
A variant of Worley noise that produces blunted and cornered features.
Manhattan Cellular F1
A variant of Worley F1 noise that uses Manhattan distance calculation. Useful when you want unusual-looking noise.
Manhattan Cellular F2-F1
A variant of Worley F2-F1 noise that uses Manhattan distance calculation. Useful when you want unusual-looking noise.
Chebyshev Cellular F1
A variant of Worley F1 noise that uses Chebyshev distance calculation. Useful when you want unusual-looking noise.
Chebyshev Cellular F2-F1
A variant of Worley F2-F1 noise that uses Chebyshev distance calculation. Useful when you want unusual-looking noise.
Frequency
The frequency of the noise. Higher values give smaller scaled details in the noise.
Offset
The offset of the input into the noise function. If you visualize the noise as a 2D graph or 3D height field, this has the effect of “panning” across the space of possible noise outputs. If you have the general noise effect you want but just want to get a different set of values for a different look, try changing the offset.
Period
When Periodic is on, the multiple of the input range before the noise pattern repeats.
Note
If Lacunarity is not 2, successive octaves will not have matching periods so a periodic noise won’t be built.
Note
Some noise types have an implicit frequency scale that must be taken into account.
Fractal ¶
Fractal Type
None
Does not add any additional noise on top of the basic noise.
Standard
Adds pseudo-random noise on top of the basic output.
Terrain
Adds noise like “Standard” but dampens the noise in the valleys, which can be useful for generating mountainous terrain.
Hybrid
Like terrain, but with more sharpness in the valleys.
Max Octaves
The number of iterations of distortion to add to the output of the basic noise. The more iterations you add, the more “detailed” the output. Note that the output may have fewer octaves than this parameter (that is, increasing the parameter will eventually stop adding detail), because the node eventually stops when there’s no more room to add more detail in the output.
Lacunarity
The frequency increment between iterations of fractal noise added to the basic output. Note that you can use a negative value.
Roughness
The scale increment between iterations of fractal noise added to the basic output. The higher the value the larger the “jaggies” added to the output. You can use a negative value for roughness.
Warping ¶
Enable Lattice Warp
Adds “stringiness” or “wiriness” to standard noise.
Accumulate Lattice Warp
When Lattice Warp is on, this accumulates the warp for each iteration (octave) of added fractal noise. When used in images, this can add interesting smudgy effects, and interesting landmarks when used for terrain.
Freq
Enable Gradient Warp
Enables a slider to widen the peaks or valleys of the noise output.
Accumulate Gradient Warp
When Lattice Warp is on, this accumulates the warp for each iteration (octave) of added fractal noise. When used in images, this can add interesting smudgy effects, and interesting landmarks when used for terrain.
Flow Rotation
When Noise type is “Flow”, this controls the rotation of the “swirl”, from 0 to 1. Because this parameter is fractional, you can’t just use $F to animate it, since all integral values will look the same, representing a complete revolution. Instead, try something like $FF / 100.
Output Correction ¶
Bias
Enables the bias controls to nudge values up or down.
Gain
Enables the gain controls to increase or decrease the contrast.
Complement
Outputs the numerical complement (1 - x) of the computed noise. Basically turns the output upside-down.
Output Range (Clamped)
Enables the New minimum and New maximum parameters to allow you to map the noise, which is normally in the [0,1] range, to a different range of values.
Final Amplitude
Scales the final conditioned output up or down.
Fire Temperature Field ¶
The controls on this tab allow you to change the look of the Fire Temperature Field, which is convert to the fire’s color. The operations are performed in the order they're listed in.
Density Volume
The name of the smoke density volume to be rendered.
Shape ¶
Fit to Range (Unclamped)
Maps a range of input values to a different output range.
Source Range
The range of input values.
Target Range
The range of output values.
Use Lookup Ramp
Maps input values to the ramp values, giving find-grained control over the shape of the field.
Use Fit to Range to controls which range of values is used to look up the ramp.
Ramp Boundaries
How to compute the result for inputs below/above the ramp’s range.
Hold
Returns the value at the nearest end of the ramp (for example, if the
ramp’s range is 0-1, and the input is -10, it will return the
ramp value for 0).
Cycle
Repeats the ramp continuously outside the range.
Cycle-Accumulate
Like “Cycle”, but starts each cycle relative to the end value of the previous cycle.
Mirror
Cycles before/after the range are mirror images (reversed) of one another. The first cycle is not mirrored.
Slope
Extends a line using the slope at the beginning/end of the ramp range.
Ramp
The lookup ramp.
Contour
Increases or decreases contrast for values at the bottom of the input range. This is sometimes useful to control feathering in volume fields.
Soft Clip
Increases or decreases contrast for values at the top of the input range. This is sometimes useful to control feathering in volume fields.
Clamp at Lower Limit
Clamp values to a lower limit.
Clamp at Upper Limit
Clamp values to an upper limit.
Final Scale
A multiplier on the final value.
Noise ¶
Enable
Whether to add any noise to this field.
Mode
Controls how the noise is applied to this field.
Offset (Field + Noise)
The noise value is added to the field value.
Scale (Field + Noise)
The field value is multiplied with the noise value.
Type
The type of noise to generate. Different algorithms give noise with different characteristics.
Fast
The default. A faster and more interesting variant of Perlin noise.
Frequency is scaled by 1.25.
Sparse Convolution
Sparse Convolution noise is similar to Worley noise. Does not have artifacts at grid points.
Frequency is scaled by 1.25.
Alligator
Produces a bumpy output. Named for its alleged resemblance to alligator skin.
Frequency is scaled by 1.64.
Perlin
A noise where the visual details are the same size. Wikipedia article
Perlin Flow
A noise that’s stable over time, like a rotated Perlin noise, useful to create noise that seems to swirl and flow smoothly across time. Use the Flow rotation parameter below to control the rotation.
Simplex
A noise similar to Perlin but the noise lattice is on a tetrahedral mesh rather than a grid. This can avoid the grid patterns often visible in Perlin noise.
Worley Cellular F1
Produces cellular features similar to plant cells, ocean waves, honeycombs, cratered landscapes, and so on. Wikipedia article
Worley Cellular F2-F1
A variant of Worley noise that produces blunted and cornered features.
Manhattan Cellular F1
A variant of Worley F1 noise that uses Manhattan distance calculation. Useful when you want unusual-looking noise.
Manhattan Cellular F2-F1
A variant of Worley F2-F1 noise that uses Manhattan distance calculation. Useful when you want unusual-looking noise.
Chebyshev Cellular F1
A variant of Worley F1 noise that uses Chebyshev distance calculation. Useful when you want unusual-looking noise.
Chebyshev Cellular F2-F1
A variant of Worley F2-F1 noise that uses Chebyshev distance calculation. Useful when you want unusual-looking noise.
Frequency
The frequency of the noise. Higher values give smaller scaled details in the noise.
Offset
The offset of the input into the noise function. If you visualize the noise as a 2D graph or 3D height field, this has the effect of “panning” across the space of possible noise outputs. If you have the general noise effect you want but just want to get a different set of values for a different look, try changing the offset.
Period
When Periodic is on, the multiple of the input range before the noise pattern repeats.
Note
If Lacunarity is not 2, successive octaves will not have matching periods so a periodic noise won’t be built.
Note
Some noise types have an implicit frequency scale that must be taken into account.
Fractal ¶
Fractal Type
None
Does not add any additional noise on top of the basic noise.
Standard
Adds pseudo-random noise on top of the basic output.
Terrain
Adds noise like “Standard” but dampens the noise in the valleys, which can be useful for generating mountainous terrain.
Hybrid
Like terrain, but with more sharpness in the valleys.
Max Octaves
The number of iterations of distortion to add to the output of the basic noise. The more iterations you add, the more “detailed” the output. Note that the output may have fewer octaves than this parameter (that is, increasing the parameter will eventually stop adding detail), because the node eventually stops when there’s no more room to add more detail in the output.
Lacunarity
The frequency increment between iterations of fractal noise added to the basic output. Note that you can use a negative value.
Roughness
The scale increment between iterations of fractal noise added to the basic output. The higher the value the larger the “jaggies” added to the output. You can use a negative value for roughness.
Warping ¶
Enable Lattice Warp
Adds “stringiness” or “wiriness” to standard noise.
Accumulate Lattice Warp
When Lattice Warp is on, this accumulates the warp for each iteration (octave) of added fractal noise. When used in images, this can add interesting smudgy effects, and interesting landmarks when used for terrain.
Freq
Enable Gradient Warp
Enables a slider to widen the peaks or valleys of the noise output.
Accumulate Gradient Warp
When Lattice Warp is on, this accumulates the warp for each iteration (octave) of added fractal noise. When used in images, this can add interesting smudgy effects, and interesting landmarks when used for terrain.
Flow Rotation
When Noise type is “Flow”, this controls the rotation of the “swirl”, from 0 to 1. Because this parameter is fractional, you can’t just use $F to animate it, since all integral values will look the same, representing a complete revolution. Instead, try something like $FF / 100.
Output Correction ¶
Bias
Enables the bias controls to nudge values up or down.
Gain
Enables the gain controls to increase or decrease the contrast.
Complement
Outputs the numerical complement (1 - x) of the computed noise. Basically turns the output upside-down.
Output Range (Clamped)
Enables the New minimum and New maximum parameters to allow you to map the noise, which is normally in the [0,1] range, to a different range of values.
Final Amplitude
Scales the final conditioned output up or down.
| See also |