Node Reference

Note

The nodes in this section are Eddy’s API nodes, not the nodes that are available in the Eddy for Nuke plugin. While there may be overlap and similarities, there may also be significant differences, so we recommend using the Eddy for Nuke specific documentation first for information about the Nuke nodes.

Core nodes

Node

An empty node, which has no plugs or properties. Creating an instance of this node can still be useful, as you can add your own arbitrary properties and expose them as output plugs. This can be necessary to pass a value to a node which has declared an input as a plug instead of a property. It also allows the same property to be connected to multiple nodes, avoiding redundantly setting the same value on multiple properties.

Bounds

Creates an axis-aligned bounding box.

Properties	Type	Default	Description
transform	M44f	Identity	Transform is applied to a unit cube to define the bounding box. If the transform has rotation then a bounding box containing the rotated box will be returned.

Output plugs	Type	Description
bounds	Box3f	The axis-aligned bounding box.

CacheLoader

Reads a volume cache from disk and converts it to a channel set. If the cache is too large to fit in available GPU memory the voxel size gain can be used to coarsen the cache. This reduces the memory footprint but also the resolution of the resulting volume.

Properties	Type	Default	Description
file	String		File name of the cache to load
voxel_size_gain	Float	1.0	Allows the voxel size to be increased, effectively loading at a lower resolution
load_constant_tiles	Bool	True	Also load VDB tiles that represent constant regions (e.g. the interior of an SDF)
channel_list	ChannelList		Specifies which channels to load and their properties
suppress_missing_file_error	Bool	False	Allows suppression of the error due to the file not being bound, an empty ChannelSet will be silently returned.
load_all_channels	Bool	False	Requests that all channels in the cache be loaded, they do not need to be explicitly listed in the channel_list property.
on_error	String	“error”	Sets the behavior when there is a problem loading a file. See File Error Modes for more information.

Output plugs	Type	Description
channel_set	ChannelSet	The ChannelSet containing the loaded voxel fields.

CacheWriter

Writes a set of voxel fields in the OpenVDB file format.

When evaluated at a time that is not the current simulation time, this node can also read back a previously saved cache.

Properties	Type	Default	Description
auto_cache_path	Bool	False	Enable automatic Nuke caching of channel set data. This has no effect when used from the API.
file	String		The file name of the cache to be written
channel_list	ChannelList		Allows selection of the channels to write
overwrite	Bool	False	Determines if existing cache files will be overwritten
use_write_range	Bool	False	Only write frames that are within the specified range
write_range_start_frame	Float	1.0	The first frame which will be written
write_range_end_frame	Float	150.0	The last frame which will be written
allow_write	Bool	True	Specifies if cache writing is enabled.
allow_read	Bool	False	Specifies if previously saved caches can be read back, when this node is evaluated at times earlier than the current simulation.

Input plugs	Type	Description
channel_set	ChannelSet	The ChannelSet containing the fields to be written.

Output plugs	Type	Description
channel_set	ChannelSet	Either the input ChannelSet just passed through the node, or a previous cache that has been read back.

Camera

Creates a Camera data type.

Properties	Type	Default	Description
transform	M44f	Identity	Transform of the camera in world space
vertical_FOV	Float	pi*3/8	Vertical field of view, measured in radians
horizontal_FOV	Float	pi/2	Horizontal field of view, measured in radians
near_plane	Float	0.0001	Near clipping plane distance from the camera
far_plane	Float	1000.0	Far clipping plane distance from the camera

Output plugs	Type	Description
camera	Camera	The camera data.

ChannelSet

Combines multiple input ChannelSets and Fields into a single result ChannelSet.

Channel names can be provided for the fields that are being included in the new ChannelSet. If an input field is given the same name as a pre-existing channel in an input ChannelSet, then it will replace that channel in the result.

Properties	Type	Default	Description
field_names	String		A comma separated list of channel names for the input fields. Fields without a name will be given a default name.

Input plugs	Type	Description
channel_sets	ChannelSet (array, optional)	Zero or more ChannelSets to be combined into the result ChannelSet.
fields	Field (array, optional)	Zero of more Fields to be combined into the result ChannelSet.

Output plugs	Type	Description
channel_set	ChannelSet	The result ChannelSet containing all of the input channels and fields.

Collider

The collider node represents collision objects in the simulation space with which an Eddy simulation element can interact. Each collider is made up of a Signed Distance Field (SDF) representing the collision object geometry and a velocity vector channel representing the object motion.

Input plugs	Type	Description
field	Field (Scalar)	The signed-distance field describing the collision object surface.
velocity_field	Field (Vector, optional)	The velocity field of the collision object.

Output plugs	Type	Description
collider	Collider	The collider data which can be passed to a simulation element.

CreateGridBounds

The CreateGridBounds node allows to refine or coarsen a single or a collection of bounding boxes.

Properties	Type	Default	Description
size	Float	0.0	The uniform bounding box size used to fill the input bounding boxes.
levels	Int	0	The number of hierarchical coarsening levels used to reduce the overall number bounding boxes.

Input plugs	Type	Description
bounds	EddyBounds	Eddy bounds that will be coarsened/refined.

Output plugs	Type	Description
bounds	EddyBounds	Eddy bounds generated by the coarsening/refinement operation

Emitter

Emitters are typically used with an Eddy simulation element. An emitter can for example add smoke density or temperature to a specific location in space. It can also modify existing data during a simulation - for example by guiding the velocity channel of a simulation using external velocity data as a target.

Properties	Type	Default	Description
mode	String	“add”	Emission mode specifies how the emission value should be composited onto the existing value. See Emission Modes for the available modes.
insert_bounds	Bool	True	Inserts the bounding boxes of the connected field into the voxel layout, ensuring the space is allocated before the emission begins.
multiplier	Float	1.0	Scales the emitted value
direction_guide_strength	Float	1.0	VectorBlend mode parameter that controls how fast the direction of the guided channel changes to match the emitted direction
acceleration_guide_strength	Float	1.0	VectorBlend mode parameter that controls how fast the magnitude of the guided channel increases to match the emitted magnitude
deceleration_guide_strength	Float	1.0	VectorBlend mode parameter that controls how fast the magnitude of the guided channel decreases to match the emitted magnitude

Input plugs	Type	Description
field	Field	The field containing the values to emit.

Output plugs	Type	Description
emitter	Emitter	The emitter data which can be passed to a simulation element.

ExtractBounds

Extracts the bounds from a mesh or field. These bounds can then be used by other nodes such as the SetBounds or simulation element nodes.

Properties	Type	Default	Description
mode	String	“RootBounds”	Chooses what type of bounds to extract from the field. See Extract Bounds Modes for the available modes.

Input plugs	Type	Description
field	Field (optional)	A field from which to extract bounds.
compoundmesh	CompoundMesh (optional)	A compound mesh from which to extract bounds.

Output plugs	Type	Description
bounds	Bounds	The bounds extracted from the field and/or mesh.

MeshToVolume

This node converts a mesh to a channel set of narrow band volumes.

Narrow band data is volume data only valid within a certain distance from the mesh surface as controlled by the Band Width parameter. Outside this band the channel(s) will have a constant (ambient) value. The computation time required to generate the channel set as well as the memory required to store it increases rapidly with increased Band Width so whenever possible strive to use a low Band Width value.

The dimensions of the output are determined by the combined bounding box of the input geometry. Meshes should to be a closed manifold whenever possible. If not manifold the mesh surface will be interpreted as a shell with a thickness defined by the shell width parameter.

The mesh surface itself is returned as an SDF channel named ‘distance’. Mesh primvar channels will be returned as corresponding fields, and the fields will respect the mesh connectivity when interpolating, i.e. UV channels will not interpolate over non-adjacent faces. If a velocity channel is requested then the velocity channel will include the velocity due to the individual mesh transforms.

Properties	Type	Default	Description
feature_size	Float	0.1	Size of the smallest features captured by the resulting volume. Should ideally be less than the smallest feature of the mesh
bandwidth	Int	4	Number of voxels defining the narrow band
shell_width	Float	1.0	Artifical thickness for meshes that are not watertight. Specified in units of the number of voxels.
generate_vertex_velocities	Bool	True	Calculates local space vertex velocities directly from the mesh vertices, overriding any existing vertex velocity channels.
channel_list	ChannelList		Channels to be voxelized.

Input plugs	Type	Description
compoundmesh	CompoundMesh	The source mesh to convert to a set of fields.

Output plugs	Type	Description
channelset	ChannelSet	The ChannelSet containing the voxelized fields.

ParticleToVolume

Voxelizes a ParticleSystem, returning a ChannelSet containing a SDF channel for the particle surfaces. Particles can be voxelized as streaks by supplying a velocity and radius channel.

Properties	Type	Default	Description
feature_size	Float	0.1	Size of the smallest features captured by the resulting volume. Should be less than the smallest particle radius
default_radius	Float	0.1	Default radius of each particle. Used when a radius input channel is not provided.
streak_multiplier	Float	1.0	Length of streaks behind each particle
streak_falloff	Float	0.0	Rate of particle radius falloff along the streak
channel_list	ChannelList		List of channels to voxelize.

Input plugs	Type	Description
particles	ParticleSystem	The source particle system to voxelize.

Output plugs	Type	Description
channel_set	ChannelSet	The ChannelSet containing the voxelized fields.

PruneBounds

Samples the supplied volume in the area of each provided bounding box 4x4x4 times and deletes it if none of the samples fall within the valid range.

Properties	Type	Default	Description
min_valid_range	Float	0.0	Minimum value threshold that each bounding box will get tested against.
max_valid_range	Float	1.0	Maximum value threshold that each bounding box will get tested against.

Input plugs	Type	Description
bounds	Bounds	The source bounding box data.
field	Field	The scalar field providing the validity samples.

Output plugs	Type	Description
bounds	Bounds	The decimated output bounding box data.

Switch

Evaluates and returns only one of multiple connected inputs.

Properties	Type	Default	Description
select	Int	0	The array index of the input to be evaluated.

Input plugs	Type	Description
inputs	Any (array, optional)	The available inputs. Only one of these will be evaluated, based on the ‘select’ property.

Output plugs	Type	Description
output	Any	The result of evaluating the selected input.

Transform

Specifies a transformation matrix. Allows a parent transformation to be specified, enabling a transformation hierarchy.

Properties	Type	Default	Description
transform	M44f	Identity	The transformation matrix.

Input plugs	Type	Description
parent_transform	M44f (optional)	Optional parent transformation, enabling a transformation hierarchy to be defined.

Output plugs	Type	Description
transform	M44f	The result transformation matrix. If a parent was specified then this will be the combined transformation.

VolumeVisualizer

Associates a field with parameters describing how it should be visualized.

Properties	Type	Default	Description
enabled	Bool	True	Enables drawing
draw_bounds	Bool	False	Enable drawing of the overall bounding box wireframe
draw_subbounds	Bool	False	Enable drawing of the active space wireframe for sparse fields
width	Float	1.3	Multiplier to scale the bounding box size, or sets the bounding box size when the field has no bounds
force_sdf	Bool	False	Forces iso surface display mode
scalar_resolution	Int	64	Number of samples along the dominant axis of channel bounding box
ss_mult_primary	Float	1.0	The primary integration stepsize when integrating fog volume
ss_mult_secondary	Float	1.0	The secondary integration stepsize towards light sources when integrating fog volume
density_gain	Float	1.0	Multiplies the density when integrating the fog volume
shadow_density_gain	Float	1.0	Multiplies the shadow intensity when integrating the fog volume
light_color	Color3f	[1.0, 1.0, 1.0]	Color of the primary light source
light_position_relative	Bool	True	When enabled the light position is relative to the channel bounds, instead of being in world space
light_position	V3f	[2.0, 2.0, 2.0]	Position of the primary light source
vector_resolution	Int	32	Number of samples along the dominant axis of channel bounding box
vector_steps	Int	3	Number of segments of each vector trail
vector_scale	Float	0.0	Length multiplier for each vector trail segment
vector_min_length	Float	0.0	Vector magnitudes approaching this will be at the lower end of the heatmap spectrum. Magnitudes below this limit will not be drawn.
vector_max_length	Float	1.0	Vector magnitudes approaching this will be at the upper end of the heatmap spectrum. Should be larger than Vector Min Length.
vector_transparency	Bool	False	Enables transparency depth sorting for correct color display
use_crop_window	Bool	False	Enable corner point handles to adjust the visualizer draw region
crop_bbox	Box3f		The bounding box to crop the visualizer draw region

Input plugs	Type	Description
field	Field	The field to be visualized.

Output plugs	Type	Description
visualizer_data	VisualizerData	The visualizer data.

VolumeDebugVisualizer

Associates a field with parameters describing how it should be numerically visualized for debugging purposes.

Properties	Type	Default	Description
enabled	Bool	True	Enables drawing
draw_bounds	Bool	False	Enable drawing of the overall bounding box wireframe
draw_subbounds	Bool	False	Enable drawing of the active space wireframe for sparse fields
width	Float	1.3	Multiplier to scale the bounding box size, or sets the bounding box size when the field has no bounds
resolution	Int	8	Number of samples along the dominant axis of channel bounding box
text_color_scale	Bool	True	Field values affect the numeric visualization text color.
text_color	Color3f	[1.0, 1.0, 1.0]	The color of the numeric visualization text
text_scale	Float	1.0	Scales the size of the text
precision	Int	3	The floating point precision, controls how many values behind the comma of the displayed text
scientific	Bool	False	Use scientific notation to display floating point numbers
draw_background	Bool	True	Adds a background behind each text to make the text more readable
background_color	Color3f	[0.75, 0.75, 0.75]	The color of the background area.
use_value_range	Bool	False	Only values that are within the range specified will be displayed. For vector values the magnitude is used to check the range
min_value_range	Float	0.0001	Minimum range of the values that will be displayed
max_value_range	Float	1.0	Maximum range of the values that will be displayed
use_crop_window	Bool	False	Enable corner point handles to adjust the visualizer draw region
crop_bbox	Box3f		The bounding box to crop the visualizer draw region

Input plugs	Type	Description
field	Field	The field to be numerically visualized.

Output plugs	Type	Description
visualizer_data	VisualizerData	The visualizer data.

ImageWriter

Saves an image to a file.

Properties	Type	Default	Description
filename	String		Filename of the image to write.

Input plugs	Type	Description
image	Image	The image to save.

Output plugs	Type	Description
image	Image	Pass-through of the input image.

SunSky

Creates an image of the sky and optionally the sun, suitable for use as an environment light, based on various physical and standardized sky models. See SunSkyRefLabel for more details.

Properties	Type	Default	Description
width	Int	640	Width of the generated image
height	Int	480	Height of the generated image
color_space	String	“sRGB”	Color space of the generated image. See Color spaces for the available color spaces.
sky_model	String	“PhysicalSpectral”	Specifies the type of sky model, can be either a physical model or a standardized model. See Sky Model types for the available types.
include_direct_light	Bool	False	Specifies whether direct light, i.e. the solar disc itself, should be included in the image
sun_direction_mode	String	“Angles”	Specifies how the sun direction should be described. See Sky Sun direction modes for the available modes.
sun_zenith	Float	30.0	The zenith angle of the sun, in degrees. Zero is directly overhead, 90 degrees is at the horizon.
sun_azimuth	Float	60.0	The azimuth angle of the sun, in degrees. Zero degrees is the +Z direction, or north (middle of the image). 270 degrees is the +X direction, or west (left half of the image).
sun_direction	V3f	[1.0, 1.0, 0.0]	The sun direction specified directly. North (middle of the image) is (0,0,1), West (left half of the image) is (1,0,0), directly overhead is (0,1,0).
latitude	Float	-41.3	Latitude of location on Earth, in degrees. North is positive and South is negative.
longitude	Float	174.8	Longitude of location on Earth, in degrees. East is positive and West is negative.
year	Int	2017	Use negative for BC, i.e. 2 BC is -1. Valid dates must be after Nov 23, 4714 BC.
month	Int	10	Month, specified as a number from 1 to 12
day	Int	18	The day of the month, specified as a number from 1 to 31
hours	Float	15.0	The time of day in hours, specified in UT (i.e. GMT), not the local time. Between 0.0 and 24.0, hours after midnight.
minutes	Float	0.0	Minutes, between 0.0 and 60.0
seconds	Float	0.0	Seconds, between 0.0 and 60.0
cie_type	Int	12	CIE sky type, from 1 to 15. Selected values are 1 which is the CIE Standard Overcast Sky, 5 which is a sky of uniform luminance, 12 which is the CIE Standard Clear Sky, low luminance turbidity, and 13 which is the CIE Standard Clear Sky, polluted atmosphere.
turbidity	Float	2.0	Turbidity specifies the cloudiness or haziness of the sky
solar_illuminance	Float	20.0	Illuminance of the sun at the top of the atmosphere. Physically this is about 132,000 lux. The default however is just set to 20.0 in order to get colors in a more convenient range by default.
solar_illuminance_exposure	Float	0.0	An exposure value to scale the solar illuminance
solar_irradiance	Float	0.2	Irradiance of the sun at the top of the atmosphere, physically this is about 1361 W/m^2, default however is just 0.2 in order to get colors in a more convenient range by default.
solar_irradiance_exposure	Float	0.0	An exposure value to scale the solar irradiance
solar_color	Color3f	[1.0, 0.9, 0.87]	Color of the sun, in the specified color space, this will be scaled by the solar illuminance value. The physical XYZ value is about (0.97, 1.0, 1.04), or in sRGB about (1.1, 0.98, 0.85). Default value is set to the proportional sRGB value (1.0, 0.9, 0.87) for convenience.
planet_radius	Float	6360000.0	Radius of the planet in metres, for earth this is about 6,360,000 m
atmosphere_height	Float	60000.0	Height of the atmosphere in metres, this is used to determine ray lengths. For earth we use 60,000 m as density is negligible at that height.
scale_height_rayleigh	Float	7994.0	Scale height in metres of atmosphere for Rayleigh scattering, i.e thickness of the atmosphere if density was uniform.
scale_height_mie	Float	1200.0	Scale height in metres of atmosphere for Mie scattering due to aerosols, i.e thickness of the atmosphere if density was uniform.
elevation	Float	1.0	Elevation of viewer in metres
mie_extinction_coefficient	Float	2.1e-5	Mie extinction coefficient at sea level, we use 2.1e-5 as the default, higher values can be used to simulate pollution
mie_scattering_albedo	Float	0.9	Mie scattering albedo, default is 0.9
mie_phase_coefficient	Float	0.76	Mie phase function coefficient, default is 0.76
ozone_concentration	Float	8e-6	Maximum ozone concentration in the atmosphere, default is 8 parts per million.
ozone_custom_ramp	Bool	False	Allows a custom ramp to be set which specifies how ozone concentration varies with altitude. If a custom ramp is not used, a default ramp will be used which has the ozone layer in the 30-35km region.
ozone_altitude_ramp	FloatRamp		A ramp which will scale the ozone concentration based on the altitude. The X-axis corresponds to height, with 1.0 corresponding to the total height of the atmosphere, and the Y-axis is the value which will scale the ozone concentration.
sample_count	Int	32	How many integration samples to take
physical_rayleigh_scattering	Bool	True	Enable to use physically calculated rayleigh scattering constants
rayleigh_scattering	V3f	[3.8e-6, 13.5e-6, 33.1e-6]	The rayleigh scattering coefficients in the specified color space
direct_solar_illuminance	Float	20.0	Illuminance of the sun at the top of the atmosphere. Physically this is about 132,000 lux. The default however is just set to 20.0 in order to get colors in a more convenient range by default.
direct_solar_illuminance_exposure	Float	0.0	An exposure value to scale the solar illuminance
solar_angular_diameter	Float	0.5357	Sun angular diameter, measured in degrees. Default is 0.5357 degrees. This is used only for the solar disc when direct light is included, it does not change the sun from being treated as a directional light.
sky_tint	Color3f	[1.0, 1.0, 1.0]	Sky tint, will be applied in the specified color space
sky_tint_exposure	Float	0.0	An exposure value to scale the sky tint
direct_light_tint	Color3f	[1.0, 1.0, 1.0]	Direct light tint, will be applied in the specified color space
direct_light_tint_exposure	Float	0.0	An exposure value to scale the direct light tint

Input plugs	Type	Description
camera	Camera (optional)	An optional camera that will be used to render just the part of the environment map seen by the camera. Note that the position of the camera is not used, the elevation property must still be set directly.
deep_clip_image	DeepImageGenerator (optional)	An optional deep image that will be used to create a clipping depth for the atmosphere rays in the physical sky models. This is useful to compute atmospheric hazing over a source deep image.

Output plugs	Type	Description
image	ImageGenerator	The ImageGenerator that can be used to create the environment map.
deep_image	DeepImageGenerator	The DeepImageGenerator that can be used to create the deep image of the sky.

Field nodes

BoxField

Creates a box signed-distance field.

Properties	Type	Default	Description
dimensions	V3f	[1.0, 1.0, 1.0]	Dimensions of the box in scene units
transform	M44f	Identity	Transform of the box in world space.

Output plugs	Type	Description
field	Field (Scalar)	The box field.

ChannelSetField

Extracts a single field from a ChannelSet.

Properties	Type	Default	Description
mode	String	“scalar”	Selects what type of field to extract from the ChannelSet. Can be “scalar” or “vector”.
channel	String		The name of the channel to extract.
transform	M44f	Identity	An additional transform to apply to the extracted field.

Input plugs	Type	Description
channel_set	ChannelSet	The ChannelSet containing the field to be extracted.

Output plugs	Type	Description
field	Field (Scalar)	The extracted field.

ComponentField

Constructs a vector channel from three input scalar channels representing the x, y and z components of the vector. If an input componnet is not connected the value of that component is assumed to be zero.

This node is useful when one wants to manually bundle together three scalar channels into a vector channel for use as for example guide forces for a simulation.

For the inverse operation (i.e. extracting a component of a vector channel as a scalar field) see the MathNode.

Properties	Type	Default	Description
transform_type	String	“Vector”	Specifies how this vector field should behave when transformed. See Vector Transform Types for the available types.

Input plugs	Type	Description
fieldX	Field (Scalar, optional)	The scalar field defining the X component of the result.
fieldY	Field (Scalar, optional)	The scalar field defining the Y component of the result.
fieldZ	Field (Scalar, optional)	The scalar field defining the Z component of the result.

Output plugs	Type	Description
field	Field (Vector)	The vector field constructed by combining the three component fields.

CompositeField

Composites together multiple field inputs.

Properties	Type	Default	Description
mode	String	“add”	Type of compositing operation performed by the node. See Compositing Modes for the available modes.
first_bound_only	Bool	False	Specifies the result bounds should be the bounds of the first input only.

Input plugs	Type	Description
fields	Field (array)	The input fields to be composited.

Output plugs	Type	Description
field	Field	The result field.

ConstantField

Generates a field with a constant value everywhere in space.

Properties	Type	Default	Description
mode	String	“scalar”	The type of constant field to create
transform_type	String	“Vector”	Specifies how this vector field should behave when transformed. See Vector Transform Types for the available types.
scalar_value	Float	1.0	The constant scalar value of the field
vector_value	V3f	[0.0, 0.0, 0.0]	The constant vector value of the field
transform	M44f	Identity	Transform to apply to the field.

Output plugs	Type	Description
field	Field	The result field.

CylinderField

Creates a cylinder signed-distance field.

Properties	Type	Default	Description
radius	Float	0.3	Radius of the cylinder in scene units
height	Float	1.0	Height of the cylinder in scene units
transform	M44f	Identity	Transform of the cylinder.

Output plugs	Type	Description
field	Field (Scalar)	The result field.

ExpressionField

Creates a field defined by an expression script which can be evaluated to determine the value of the field at each point.

Properties	Type	Default	Description
field_type	String	“Scalar”	The type of the field to create. See Field Types for the available types.
language	String	“Python”	The language to use for the field expression. See Script Language Types for the available types.
expression_python_scalar	String		Python script for the scalar field expression
expression_python_vector	String		Python script for the vector field expression
expression_cpp_scalar	String		C++ script for the scalar field expression
expression_cpp_vector	String		C++ script for the vector field expression
transform	M44f	Identity	Transform to apply to the field.

Input plugs	Type	Description
bounds	Box3f (optional)	Provides the bounding box of the field.

Output plugs	Type	Description
field	Field (Scalar)	The result field.

FilterField

Performs a filtering operation on the input channel. This will produce blur like effects or act as a low pass filter.

Properties	Type	Default	Description
mode	String	“box”	The filtering operation to perform on the input. See Filter Function Modes for the available modes.
kernel_width	Float	1.0	The size of the filtering kernel, measured in distance units.

Input plugs	Type	Description
field	Field	The source field on which to perform the finite differencing operation.

Output plugs	Type	Description
field	Field (Vector)	The result field.

FiniteDifferenceField

Perform finite difference operations on the input channel. A finite difference operation is an approximation of the equivalent mathematical operator - for example the gradient operator.

Properties	Type	Default	Description
mode	String	“gradient”	The type of finite differencing operation to perform. See Finite Difference Modes for the available modes.
stencil_width	Float	0.2	The size of the stencil to use for finite differencing, measured in distance units.

Input plugs	Type	Description
field	Field	The source field on which to perform the finite differencing operation.

Output plugs	Type	Description
field	Field (Vector)	The result field.

ImageField

Creates a field from an image, either by stretching the image into a box, or projecting the image using a camera.

Properties	Type	Default	Description
mode	String	“scalar”	The type of image field to create. Vector fields will return the RGB color in the XYZ vector components. Can be “scalar” or “vector”.
transform_type	String	“Vector”	Specifies how this vector field should behave when transformed. See Vector Transform Types for the available types.
dimensions	V3f	[1.0, 1.0, 0.1]	The size of the field, when not using a camera projection
keep_aspect_ratio	Bool	True	Adjusts the Y dimension to maintain the image aspect ratio, when not using a camera projection
as_texture	Bool	False	Field will be sampled directly in texture space instead of world space. Transform/camera are not used.
image	Image		The image to sample for the field values
override_projection_matrix	Bool	False	Specifies that the ‘projection_matrix’ property should be used instead of the camera’s projection matrix.
projection_matrix	M44f	Identity	Projection matrix to use if ‘override_projection_matrix’ is true.
transform	M44f	Identity	Transform to apply to the field when not using a camera.

Input plugs	Type	Description
camera	Camera (optional)	Optionally projects the image using the camera.

Output plugs	Type	Description
field	Field (Scalar)	The result field.

InstanceField

Combines multiple fields into a single field by merging multiple transformed instances.

Properties	Type	Default	Description
mode	String	“Add”	Specifies how to combine the fields. See Instance Field Modes for the available modes.
ambient_scalar	Float	0.0	The ambient scalar value, outside the instanced fields.
ambient_vector	V3f	[0.0, 0.0, 0.0]	The ambient vector value, outside the instanced fields.

Input plugs	Type	Description
instance_collection	InstanceCollection	An Eddy instance collection containing volume channels.

Output plugs	Type	Description
field	Field	The result field.

IsoMaskField

Creates a mask field from a signed-distance field.

Properties	Type	Default	Description
mode	String	“scalar”	The type of mask field to create. Can be “scalar” or “vector”.
transform_type	String	“Vector”	Specifies how this vector field should behave when transformed. See Vector Transform Types for the available types.
iso_value	Float	0.0	The value which defines the transition of the input field from inside to outside. Values smaller than this are defined as the interior.
falloff	Float	0.0	Blends the mask from the inside value to the outside value, as the input field varies from the iso value to the sum of the iso value and the falloff
scalar_inside_value	Float	1.0	Value of the mask field in the interior region of the input field
scalar_outside_value	Float	0.0	Value of the mask field in the exterior region of the input field
vector_inside_value	V3f	[1.0, 1.0, 1.0]	Value of the mask field in the interior region of the input field
vector_outside_value	V3f	[0.0, 0.0, 0.0]	Value of the mask field in the exterior region of the input field

Input plugs	Type	Description
field	Field (Scalar)	The signed-distance source field.

Output plugs	Type	Description
field	Field (Scalar)	The result field.

MathField

Perform basic mathematical operations on the input field.

Properties	Type	Default	Description
mode	String	“absolute”	The type of math operation to perform. See Math Field Modes for the availble modes.

Input plugs	Type	Description
field	Field	The source field.

Output plugs	Type	Description
field	Field (Scalar)	The result field.

OffsetLookupField

Distorts the input field through a vector field describing the displacement.

Properties	Type	Default	Description
mode	String	“trace”	The type of offset lookup operation to perform. See Offset Lookup Field Modes for the available modes.
scale	Float	1.0	Scale applied to the offset field controlling the magnitude of the offset/distortion
trace_steps	Int	1	The maximum number of offset steps to take when tracing through the field
bbox_gain	Float	1.0	Adjusts the size change of the generated bounding box for the new output channel. A value of 0.0 will keep the input bounds.

Input plugs	Type	Description
field	Field	The source field to be distorted.
offset_field	Field (Vector)	The offset vector field describing how the source should be distorted.

Output plugs	Type	Description
field	Field	The result field.

PerlinNoiseField

Generates a field containing Perlin noise.

Properties	Type	Default	Description
mode	String	“scalar”	The type of noise field to create
transform_type	String	“Vector”	Specifies how this vector field should behave when transformed. See Vector Transform Types for the available types.
seed	Int	0	Seed for the random number generator, change to get a different pattern of randomness
frequency	V3f	[1.0, 1.0, 1.0]	Frequency determines how fast the noise changes in space. Higher values produce noise that changes faster
scalar_amplitude	Float	1.0	Maximum value of the noise produced. It will vary between -amplitude and +amplitude
vector_amplitude	V3f	[1.0, 1.0, 1.0]	Maximum value of the noise produced. It will vary between -amplitude and +amplitude
octaves	Int	1	Number of octaves of noise to combine, more octaves will add higher frequency detail to the final noise
lacunarity	Float	2.0	Scale that is applied to the frequency to increase the detail in each successive octave. Should be greater than 1 in general, and avoid round numbers which might introduce artefacts into the Perlin noise
gain	Float	0.5	Scale that is applied to the amplitude in each successive octave. Generally should be less than 1 in order to fade out the higher detail
animated	Bool	False	When enabled the noise function will be a 4D perlin noise.
phase	Float	0.0	The temporal phase of the 4D noise function. Animating this parameter will change the noise over time.
transform	M44f	Identity	Transform to apply to the field.

Output plugs	Type	Description
field	Field (Scalar)	The result field.

PlaneField

Creates a plane signed-distance field.

Properties	Type	Default	Description
transform	M44f	Identity	Transform of the plane.

Output plugs	Type	Description
field	Field (Scalar)	The result field.

RemapField

Remaps the values in a field.

Properties	Type	Default	Description
oldMinValueScalar	Float	0.0	Minimum of the source range to be remapped, this value will sample the ramp at position 0.0
oldMaxValueScalar	Float	1.0	Maximum of the source range to be remapped, this value will sample the ramp at position 1.0
newMinValueScalar	Float	0.0	Minimum of the target range, this is the output value when the ramp returns 0.0
newMaxValueScalar	Float	1.0	Maximum of the target range, this is the output value when the ramp returns 1.0
oldMinValueVector	V3f	[0.0, 0.0, 0.0]	Minimum of the source range to be remapped, this value will sample the ramp at position 0.0
oldMaxValueVector	V3f	[1.0, 1.0, 1.0]	Maximum of the source range to be remapped, this value will sample the ramp at position 1.0
newMinValueVector	V3f	[0.0, 0.0, 0.0]	Minimum of the target range, this is the output value when the ramp returns 0.0
newMaxValueVector	V3f	[1.0, 1.0, 1.0]	Maximum of the target range, this is the output value when the ramp returns 1.0
ramp	FloatRamp		The ramp to use for remapping
clamp	Bool	True	Clamps the ramp to between 0 and 1

Input plugs	Type	Description
field	Field	The source field to be remapped.

Output plugs	Type	Description
field	Field	The result field.

SphereField

Creates a sphere SDF field.

Properties	Type	Default	Description
radius	Float	0.5	Radius of the sphere in scene units
transform	M44f	Identity	Transform of the sphere, scaling is allowed

Output plugs	Type	Description
field	Field (Scalar)	The result sphere field

SetBoundsField

Sets the bounds of a field. This will override any existing bounds on the field.

Input plugs	Type	Description
field	Field	The source field.
bounds	Bounds	The new bounds for the field.

Output plugs	Type	Description
field	Field	The result field with the new bounds.

TransformField

Applies a transformation to a field.

Properties	Type	Default	Description
transform	M44f	Identity	Transform to apply to the field

Input plugs	Type	Description
field	Field	The source field.

Output plugs	Type	Description
field	Field	The transformed field.

TransformVelocityField

Generates a velocity field from the input transformation. The input transformation should be keyframed in order to have a velocity.

Properties	Type	Default	Description
position_vel	Bool	True	Include translational motion (i.e. linear velocity) in the final velocity
rotation_vel	Bool	True	Include rotational motion in the final velocity
scale_vel	Bool	True	Include scaling motion in the final velocity
transform	M44f	Identity	The transform from which to extract the velocity.

Output plugs	Type	Description
field	Field (Vector)	The result velocity field.

VectorMathField

Perform vector math operations on two input channels.

Properties	Type	Default	Description
mode	String	“dot”	The type of math operation to perform. See Vector Math Field Modes for the available modes.

Input plugs	Type	Description
fieldA	Field (Vector)	The first input field.
fieldB	Field (Vector)	The second input field.

Output plugs	Type	Description
field	Field (Scalar)	The result field.

RasterizeField

Rasterizes a field into a voxel grid.

This node can be used to rasterize a field into a voxel grid. If the input field was made from a large network of expensive nodes, it can be expensive to sample. The rasterized output field is faster to sample, albeit at the cost of memory and quality. Operations which require a lot of sampling (e.g. rendering) can benefit from using a rasterized field.

Properties	Type	Default	Description
voxel_size	Float	0.1	Size of the rasterized voxels.
interpolator	String	“Trilinear”	The interpolator to use when sampling the resulting voxel field. See Interpolation Types for the available types.

Input plugs	Type	Description
field	Field	The source field to be rasterized.

Output plugs	Type	Description
field	Field	The result field.

Instancing nodes

InstanceCallsheet

This node creates a callsheet which combines multiple unique instance items into a single collection.

Properties	Type	Default	Description

Input plugs	Type	Description
instance_item	InstanceItem	Eddy instance items with unique indentifiers.

Output plugs	Type	Description
instance_callsheet	InstanceCallsheet	An Eddy callsheet.

InstanceChannelset

This node will combine all instanced channelsets into a single channelset containing all channels.

Properties	Type	Default	Description
mode_scalar	String	“Max”	The compositing mode to use when combining overlapping instances. See Instance Field Modes for the available modes.
mode_vector	String	“Avg”	The compositing mode to use when combining overlapping instances. See Instance Field Modes for the available modes.
ambient_scalar	Float	0.0	The ambient or outside value is returned in areas where no instances are present.
ambient_vector	V3f	[0.0,0.0,0.0]	The ambient or outside value is returned in areas where no instances are present.

Input plugs	Type	Description
instance_collection	InstanceCollection	An Eddy instancer for recursive instancing.

Output plugs	Type	Description
channelset	Channelset	An Eddy callsheet containing all the instanced channelsets combined into one.

InstanceItem

This node creates a generic instance item from given a supported input.

Properties	Type	Default	Description
id	Int	1	A unique identifier used to reference this item in a callsheet.
weight	Float	1.0	A probability weight to increase the chance this item gets chosen during random selection.

Input plugs	Type	Description
field	Field	An Eddy field that will be instantiated.
mesh	Mesh	An Eddy mesh that will be instantiated.
channelset	Channelset	An Eddy channelset that will be instantiated.
instancer	Instancer	An Eddy instancer for recursive instancing.

Output plugs	Type	Description
instance_item	InstanceItem	An Eddy instance item that describes the input to the instancing system.

InstanceItemVariant

This node selects an instance item from one of the given inputs randomly. This can be a simple way to add variations.

Properties	Type	Default	Description
id	Int	1	A unique identifier used to reference this item in a callsheet.
weight	Float	1.0	A probability weight to increase the chance this item gets chosen during random selection.

Input plugs	Type	Description
instance_items	InstanceItem	An Eddy instance item that will be selected based on its probability weight.

Output plugs	Type	Description
instance_item	InstanceItem	An Eddy instance item that describes the input to the instancing system.

InstanceItemVolumeCache

This node wraps a Channel set provided by a volume cache and allows to generate time offset and level of detail (LOD) variants of it. LOD variants are generated by the instancer based on the size of a voxel in camera space. Allowing the volume cache instance to generate many different LOD and time variants will however increase memory consumption as more unique instances are generated.

Properties	Type	Default	Description
id	Int	1	A unique identifier used to reference this item in a callsheet.
weight	Float	1.0	A probability weight to increase the chance this item gets chosen during random selection.
file	String	“”	Location of the .vdb file (eg: /data/cache.#.vdb )
random_offset_range	Int	100	This will pick a random time offset for each instance centered around the current frame.
voxel_size_gain	Float	1.f	Multiplier to the loaded data set voxel size used to reduce the memory requirement (but also the resolution) of the VDB cache.
max_lod_levels	Int	5	The maximum number of LOD levels allowed.
min_lod_width	Float	0.05	The minimum pixel width of a voxel in camera space when the coarsest LOD level is used.
max_lod_gain	Float	4.0	The maximum coarsening for the cache at the maximum Lod level. This gain is in addition to the base voxel size gain parameter.
screen_size	V2i	[1920,1080]	The screen size in pixels used to determine the Lod level for each cache.
suppress_missing_file_error	Bool	false	No errors are generated when a file is not found.
load_all_channels	Bool	true	When enabled all channels are loaded and the ChannelList is ignored.
load_constant_tiles	Bool	true	If disabled the cache loader will ignore OpenVDB constant tiles. This could for example be the interior of an SDF shape.
channel_list	ChannelList		Selects which channel to load from the cache, and sets channel properties such as the interpolator to be used for sampling and the vector transformation type. See Channel Set widget.

Input plugs	Type	Description

Output plugs	Type	Description
instance_item	InstanceItem	An Eddy instance item that describes the input to the instancing system.

Instancer

This node generates all the unique instances and outputs them as an instance collection which holds all different supported types.

Properties	Type	Default	Description
random_seed	Int	1237	Seed for the random number generator.

Input plugs	Type	Description
instancer	Instancer	Eddy instancers that will be built.
camera	Camera	An Eddy camera that will be used to determine the level of detail for instances where applicable.

Output plugs	Type	Description
instance_collection	InstanceCollection	An Eddy instance collection containing all the unique instances of all supported types.

ParticleInstance

The node will place instances defined in a callsheet at particle locations. There are several options to control orientation and scaling of each instance. For ease of use randomized options for most options exist, while more tight control of each instance can be achieved by using particle channels to drive attributes of each instance.

Properties	Type	Default	Description
particle_id_channel	String	“id”	Set the integer particle channel used to seed the per particle random number generator. This attribute value should be constant for the lifetime of each particle.
callsheet_mode	String	“random”	Set the mode which determines how the unique ids in the callsheet are accessed. See Instance callsheet modes for more information.
callsheet_channel	String	“”	Set the integer particle channel that will select the instance item from the callsheet. The value needs to match a unique identifier in the callsheet.
time_offset_mode	String	“none”	Set the mode which determines how the time offset is generated for each particle instance. See Instance time offset modes for more information.
time_channel	String	“”	Set the integer particle channel that will generate the frame time for each particle. It allows direct control of the instance item volume cache by passing the absolute time as a particle value.
rotation_mode	String	“random”	Set the mode which determines how the rotation of each instance is generated. See Instance rotation modes for more information.
rotation_channel	String	“”	Set the vector particle channel that will generate the rotation for each particle. The expected values are in Euler angles.
random_rotation_min	V3f	[0.0,0.0,0.0]	The minimum rotation range in Euler angles that will be used when generating random rotations for each instance.
random_rotation_max	V3f	[0.0,0.0,0.0]	The maximum rotation range in Euler angles that will be used when generating random rotations for each instance.
scale_mode	String	“random”	Set the mode which determines how the scaling of each instance is generated. See Instance scale modes for more information.
uniform_scale	Bool	true	When enabled the scaling for each axis will be determined by a single random number opposed to a random number for each axis.
random_scale_min	V3f	[0.0,0.0,0.0]	The minimum scaling range that will be used when generating a random scaling for each instance.
random_scale_max	V3f	[0.0,0.0,0.0]	The maximum scaling range that will be used when generating a random scaling for each instance.

Input plugs	Type	Description
particles	ParticleSystem	An Eddy particle system defining particle positions.
instance_callsheet	InstanceCallsheet	An Eddy instance callsheet that specifies the instance items available for instancing.

Output plugs	Type	Description
instancer	Instancer	An Eddy instancer.

RandomInstance

The node will randomly pick one of the connected instance items and place them at each location.

Properties	Type	Default	Description

Input plugs	Type	Description
instance_items	InstanceItem	An Eddy instance item that can be chosen from.
transform	M44f (array)	One or more transforms representing the transforms of each instance

Output plugs	Type	Description
instancer	Instancer	An Eddy instancer.

Particle nodes

ParticleCacheLoader

Reads an OpenVDB points cache from disk and converts it to a particle system.

Properties	Type	Default	Description
file	String	“”	File name of the cache to load.
suppress_missing_file_error	Bool	False	Allows suppression of the error due to the file not being bound, an empty Par will be silently returned.
load_all_channels	Bool	False	Requests that all channels in the cache be loaded, they do not need to be explicitly listed in the channel_list property.
on_error	String	“error”	Sets the behavior when there is a problem loading a file. See File Error Modes for more information.
channel_list	ChannelList		Selects which channel to load from the cache, and sets channel properties such as the default value. See Channel Set widget.

Input plugs	Type	Description

Output plugs	Type	Description
particles	ParticleSystem	An Eddy particle system.

ParticleCacheWriter

Writes a set of Eddy particle channels in the OpenVDB file points format, and loads back previously saved caches when scrubbing the timeline.

Properties	Type	Default	Description
file	String	“”	File name the particles will be written to.
overwrite	Bool	False	Controls whether the cache node is allowed to overwrite existing files or not.
use_write_range	Bool	False	If enabled the cache node will only write frames from the interval between Start Frame and End Frame
write_range_start_frame	Float	1.0	First frame that will be cached
write_range_start_frame	Float	150.0	Last frame that will be cached
channel_list	ChannelList		Selects which channel to write to the cache. See Channel Set widget.

Input plugs	Type	Description
particles	ParticleSystem	An Eddy particle system containing channels that will be cached to a file.

Output plugs	Type	Description
particles	ParticleSystem	An Eddy particle system.

ParticleExpression

Allows to modify particle channels via expressions.

Properties	Type	Default	Description
language	String	“Python”	The language in which the expression script is written.
expression_python	String	“def particle_expression(i_particleIndex=Int):n passn”	The script containing the function defining the field.
expression_cpp	String	“void particle_expression(const int i_particleIndex)n{n return;n}n”	The script containing the function defining the field.

Input plugs	Type	Description
particles	ParticleSystem	An Eddy particle system.

Output plugs	Type	Description
particles	ParticleSystem	An Eddy particle system.

ParticleSystem

An Eddy particle system that can be used in conjunction with other eddy particle nodes.

Properties	Type	Default	Description
start_frame	Int	1	All stored particles will be cleared whenever the current time is on or below the start frame.
channel_list	ChannelList		Selects which channels will be added to the particle system upon reset.

Input plugs	Type	Description
particles	ParticleSystem	An Eddy particle system containing channels that will be cached to a file.

Output plugs	Type	Description
particles	ParticleSystem	An Eddy particle system.

ParticleVisualizer

A visualizer for an Eddy particle system.

Properties	Type	Default	Description
enabled	Bool	True	Enables the visualizer.
color_mode	String	constant	The mode used to determine the color of a particle. See Particle Visualizer Modes for more information.
color	Color3f	[1.f,1.f,1.f]	The constant color for each particle.
color_channel	String	“”	The particle channel used to determine the color of each particle.
velocity_remap	Bool	False	When enabled, the velocity magnitude of the velocity is used to color the particles.
max_velocity	Float	2.0	The particle color turns white as the velocity magnitude approaches this value.
radius_mode	String	constant	The mode used to determine the radius of a particle. See Particle Visualizer Modes for more information.
radius	Float	1.f	This constant radius is used to display each particle.
radius_channel	String	“”	The particle channel used to determine the radius of each particle.

Input plugs	Type	Description
particles	ParticleSystem	An Eddy particle system that will be visualized.

Output plugs	Type	Description
visualizer_data	VisualizerData	The visualizer data.

Element nodes

CombustionElement

A simulation element with a combustion model. It uses a DenseVolume to store the simulation.

Properties	Type	Default	Description
dimensions	V3f	[1.5, 1.5, 1.5]	The dimensions of the computational grid in scene units
resolution	Int	128	The number of voxels along the major axis of the domain
use_grid_expansion	Bool	False	Allows the simulation world (space) to grow dynamically with the simulation
expansion_min_resolution	V3i	[32, 32, 32]	The lowest resolution allowed when using dynamic grid expansion
expansion_max_resolution	V3i	[512, 512, 512]	The highest resolution allowed when using dynamic grid expansion
expansion_delay	Int	5	The number of computation cycles between each grid expansion event
expansion_padding	Int	30	The number of empty voxels added as padding around the smoke when the simulation space is reshaped
expansion_density_threshold	Float	0.0	The smoke lower density threshold used to determine what regions of the simulation to preserve when the simulation space is reshaped
quality_mode	Bool	False	Emphasize simulation quality over speed
buoyancy_dir	V3f	[0.0, 1.0, 0.0]	The direction of the buoyancy force
kinematic_viscosity	Float	0.0	The kinematic viscosity of the fluid. Unit is m2/s
num_pressure_iterations	Int	30	The maximum number of computation cycles allowed to compute the pressure channel of the fluid
num_viscosity_iterations	Int	30	The maximum number of computation cycles allowed to solve for viscosity
pressure_error_tolerance	Float	0.0	The pressure error tolerance in terms of amount of fluid compressibility
viscosity_error_tolerance	Float	0.0	The viscosity error tolerance
use_multigrid_acceleration	Bool	True	Enable a method that greatly increases the quality of the pressure channe. Keep enabled unless you experience artifacts or stability issues
cfl_min_steps	Int	1	The minimum number of simulation steps per frame
cfl_max_steps	Int	1	The maximum number of simulation steps per frame
dt_scale	Float	1.0	Time scaling constant. 2.0 means time flows 2x faster than normal
dens_dissipation	Float	0.0	The rate by which smoke dissipates
dens_dissipation_low_thresh	Float	0.0	Smoke density threshold below which dissipation increases rapidly
dens_dissipation_low_rate_gain	Float	4.0	Multiplier on the rate of non-linear dissipation below the threshold density
use_vorticity_confinement	Bool	True	Enable a method that adds energy to vortices in the simulation
vorticity_confinement	Float	5.0	Determines the amount of energy added to the vortices
vorticity_confinement_adaptive	Bool	True	Enables a method that only injects energy into relevant regions of the simulation
vorticity_confinement_scale_energy_falloff_power	Float	1.0	Controls the distribution of the size of the features targeted by the adaptivity method. Higher values more strongly emphasises high frequencies
vorticity_confinement_adaptive_tolerance	Float	0.3	Threshold determining how aggressively the adaptivity oracle selects valid regions for energy injection
use_wavelet_turbulence	Bool	True	Enables an algorithm that synthesizes additional turbulence adding visual complexity to the simulation
wavelet_turbulence_strength	Float	30.0	Controls the magnitude of the synthesized turbulence
wavelet_turbulence_scale_energy_falloff_power	Float	3.0	Controls the distribution of the size of the features targeted by the adaptivity method. Higher values more strongly emphasises high frequencies
wavelet_turbulence_adaptive_tolerance	Float	0.1	Threshold determining how aggressively the turbulence adaptivity oracle selects valid regions for turbulence injection
cooling_rate	Float	1900.0	The rate by which the soot cools through heat exchange with the surroundings
ignition_value	Float	50.0	The temperature at which the fuel ignites
combustion_value	Float	1400.0	The temperature with which the fuel burns
carbon_value	Float	0.2	The amount of carbon residue (i.e. soot) produced per unit of fuel consumed
burn_rate	Float	3.0	The amount of fuel consumed per second as the fuel burns
fuel_expansion	Float	0.2	The amount of fuel volume gain, i.e. expansion caused per unit of fuel consumed
fuel_combustion_threshold	Float	0.2	The maximum fuel density allowed for ignition
channel_list	ChannelList		Allows specification of channel meta data like interpolation or transformation mode

Input plugs	Type	Description
density	Emitter (array, optional)	An emitter for the density channel.
temperature	Emitter (array, optional)	An emitter for the temperature channel.
fuel	Emitter (array, optional)	An emitter for the fuel channel.
velocity	Emitter (array, optional)	An emitter for the velocity channel.
colliders	Collider (array, optional)	The collision objects for the simulation.

Output plugs	Type	Description
element	DenseVolumeChannelSet	The ChannelSet containing the simulated fields.

SparseCombustionElement

A simulation element with a combustion model. It uses a SparseVolume to store the simulation.

Properties	Type	Default	Description
dx	Float	1.0	The size in scene units of the smallest feature that can be present in the simulation
initial_state_cachefile	String	None	Specify a filepath to a .vdb file that will be used to populate the initial state of the fluid channels, when the element is reset.
automatic_grid_padding	Bool	True	Enables a method that attempts to automatically find the optimal active space for the simulation
automatic_grid_padding_aggressiveness	Float	0.0	Controls how aggressively new space is added to the active set
automatic_grid_padding_max_padding	Int	16	This is a limit to the maximum distance in voxels that the active set is allowed to be expanded by the auto padding heuristic
use_grid_padding	Bool	True	Enables padding the active space based on smoke density
grid_padding_amount	Int	5	The number of voxel layers with which the active space is padded
grid_padding_density_threshold	Float	0.0	The lower density threshold that define the region of interest which is the base for the active space
grid_padding_fuel_threshold	Float	0.0	The lower fuel amount threshold that define the region of interest which is the base for the active space
quality_mode	Bool	False	Emphasize simulation quality over speed
buoyancy_dir	V3f	[0.0, 1.0, 0.0]	The direction of the buoyancy force
kinematic_viscosity	Float	0.0	The kinematic viscosity of the fluid. Unit is m2/s
num_pressure_iterations	Int	30	The maximum number of computation cycles allowed to compute the pressure channel of the fluid
num_viscosity_iterations	Int	30	The maximum number of computation cycles allowed to solve for viscosity
pressure_error_tolerance	Float	0.0	The pressure error tolerance in terms of amount of fluid compressibility
viscosity_error_tolerance	Float	0.0	The viscosity error tolerance
use_multigrid_acceleration	Bool	True	Enable a method that greatly increases the quality of the pressure channe. Keep enabled unless you experience artifacts or stability issues
cfl_min_steps	Int	1	The minimum number of simulation steps per frame
cfl_max_steps	Int	1	The maximum number of simulation steps per frame
dt_scale	Float	1.0	Time scaling constant. 2.0 means time flows 2x faster than normal
dens_dissipation	Float	0.0	The rate by which smoke dissipates
dens_dissipation_low_thresh	Float	0.0	Smoke density threshold below which dissipation increases rapidly
dens_dissipation_low_rate_gain	Float	4.0	Multiplier on the rate of non-linear dissipation below the threshold density
use_vorticity_confinement	Bool	True	Enable a method that adds energy to vortices in the simulation
vorticity_confinement	Float	2.0	Determines the amount of energy added to the vortices
vorticity_confinement_adaptive	Bool	True	Enables a method that only injects energy into relevant regions of the simulation
vorticity_confinement_scale_energy_falloff_power	Float	1.0	Controls the distribution of the size of the features targeted by the adaptivity method. Higher values more strongly emphasises high frequencies
vorticity_confinement_adaptive_tolerance	Float	0.3	Threshold determining how aggressively the adaptivity oracle selects valid regions for energy injection
use_wavelet_turbulence	Bool	True	Enables an algorithm that synthesizes additional turbulence adding visual complexity to the simulation
wavelet_turbulence_strength	Float	30.0	Controls the magnitude of the synthesized turbulence
wavelet_turbulence_scale_energy_falloff_power	Float	3.0	Controls the distribution of the size of the features targeted by the adaptivity method. Higher values more strongly emphasises high frequencies
wavelet_turbulence_adaptive_tolerance	Float	0.1	Threshold determining how aggressively the turbulence adaptivity oracle selects valid regions for turbulence injection
cooling_rate	Float	1900.0	The rate by which the soot cools through heat exchange with the surroundings
ignition_value	Float	50.0	The temperature at which the fuel ignites
combustion_value	Float	1400.0	The temperature with which the fuel burns
carbon_value	Float	0.2	The amount of carbon residue (i.e. soot) produced per unit of fuel consumed
burn_rate	Float	3.0	The amount of fuel consumed per second as the fuel burns
fuel_expansion	Float	0.2	The amount of fuel volume gain, i.e. expansion caused per unit of fuel consumed
fuel_combustion_threshold	Float	0.2	The maximum fuel density allowed for ignition
channel_list	ChannelList		Allows specification of channel meta data like interpolation or transformation mode

Input plugs	Type	Description
density	Emitter (array, optional)	An emitter for the density channel.
temperature	Emitter (array, optional)	An emitter for the temperature channel.
fuel	Emitter (array, optional)	An emitter for the fuel channel.
velocity	Emitter (array, optional)	An emitter for the velocity channel.
colliders	Collider (array, optional)	The collision objects for the simulation.
bounds	Box3f (optional)	Bounding box that constrains the expansion of the simulation.

Output plugs	Type	Description
element	SparseVolumeChannelSet	The ChannelSet containing the simulated fields.

SmokeElement

A simulation element for smoke or dust. It uses a DenseVolume to store the simulation.

Properties	Type	Default	Description
dimensions	V3f	[1.5, 1.5, 1.5]	The dimensions of the computational grid in scene units
resolution	Int	128	The number of voxels along the major axis of the domain
use_grid_expansion	Bool	False	Allows the simulation world (space) to grow dynamically with the simulation
expansion_min_resolution	V3i	[32, 32, 32]	The lowest resolution allowed when using dynamic grid expansion
expansion_max_resolution	V3i	[512, 512, 512]	The highest resolution allowed when using dynamic grid expansion
expansion_delay	Int	5	The number of computation cycles between each grid expansion event
expansion_padding	Int	30	The number of empty voxels added as padding around the smoke when the simulation space is reshaped
expansion_density_threshold	Float	0.0	The smoke lower density threshold used to determine what regions of the simulation to preserve when the simulation space is reshaped
quality_mode	Bool	False	Emphasize simulation quality over speed
buoyancy_dir	V3f	[0.0, 1.0, 0.0]	The direction of the buoyancy force
kinematic_viscosity	Float	0.0	The kinematic viscosity of the fluid. Unit is m2/s
num_pressure_iterations	Int	30	The maximum number of computation cycles allowed to compute the pressure channel of the fluid
num_viscosity_iterations	Int	30	The maximum number of computation cycles allowed to solve for viscosity
pressure_error_tolerance	Float	0.0	The pressure error tolerance in terms of amount of fluid compressibility
viscosity_error_tolerance	Float	0.0	The viscosity error tolerance
use_multigrid_acceleration	Bool	True	Enable a method that greatly increases the quality of the pressure channe. Keep enabled unless you experience artifacts or stability issues
cfl_min_steps	Int	1	The minimum number of simulation steps per frame
cfl_max_steps	Int	1	The maximum number of simulation steps per frame
dt_scale	Float	1.0	Time scaling constant. 2.0 means time flows 2x faster than normal
dens_dissipation	Float	0.0	The rate by which smoke dissipates
dens_dissipation_low_thresh	Float	0.0	Smoke density threshold below which dissipation increases rapidly
dens_dissipation_low_rate_gain	Float	4.0	Multiplier on the rate of non-linear dissipation below the threshold density
use_vorticity_confinement	Bool	True	Enable a method that adds energy to vortices in the simulation
vorticity_confinement	Float	5.0	Determines the amount of energy added to the vortices
vorticity_confinement_adaptive	Bool	True	Enables a method that only injects energy into relevant regions of the simulation
vorticity_confinement_scale_energy_falloff_power	Float	1.0	Controls the distribution of the size of the features targeted by the adaptivity method. Higher values more strongly emphasises high frequencies
vorticity_confinement_adaptive_tolerance	Float	0.3	Threshold determining how aggressively the adaptivity oracle selects valid regions for energy injection
use_wavelet_turbulence	Bool	True	Enables an algorithm that synthesizes additional turbulence adding visual complexity to the simulation
wavelet_turbulence_strength	Float	30.0	Controls the magnitude of the synthesized turbulence
wavelet_turbulence_scale_energy_falloff_power	Float	3.0	Controls the distribution of the size of the features targeted by the adaptivity method. Higher values more strongly emphasises high frequencies
wavelet_turbulence_adaptive_tolerance	Float	0.1	Threshold determining how aggressively the turbulence adaptivity oracle selects valid regions for turbulence injection
channel_list	ChannelList		Allows specification of channel meta data like interpolation or transformation mode

Input plugs	Type	Description
density	Emitter (array, optional)	An emitter for the density channel.
velocity	Emitter (array, optional)	An emitter for the velocity channel.
colliders	Collider (array, optional)	The collision objects for the simulation.

Output plugs	Type	Description
element	DenseVolumeChannelSet	The ChannelSet containing the simulated fields.

SparseSmokeElement

A simulation element for smoke or dust. It uses a SparseVolume to store the simulation.

Properties	Type	Default	Description
dx	Float	1.0	The size in scene units of the smallest feature that can be present in the simulation
initial_state_cachefile	String	None	Specify a filepath to a .vdb file that will be used to populate the initial state of the fluid channels, when the element is reset.
automatic_grid_padding	Bool	True	Enables a method that attempts to automatically find the optimal active space for the simulation
automatic_grid_padding_aggressiveness	Float	0.0	Controls how aggressively new space is added to the active set
automatic_grid_padding_max_padding	Int	16	This is a limit to the maximum distance in voxels that the active set is allowed to be expanded by the auto padding heuristic
use_grid_padding	Bool	True	Enables padding the active space based on smoke density
grid_padding_amount	Int	5	The number of voxel layers with which the active space is padded
grid_padding_density_threshold	Float	0.0	The lower density threshold that define the region of interest which is the base for the active space
quality_mode	Bool	False	Emphasize simulation quality over speed
buoyancy_dir	V3f	[0.0, 1.0, 0.0]	The direction of the buoyancy force
kinematic_viscosity	Float	0.0	The kinematic viscosity of the fluid. Unit is m2/s
num_pressure_iterations	Int	30	The maximum number of computation cycles allowed to compute the pressure channel of the fluid
num_viscosity_iterations	Int	30	The maximum number of computation cycles allowed to solve for viscosity
pressure_error_tolerance	Float	0.0	The pressure error tolerance in terms of amount of fluid compressibility
viscosity_error_tolerance	Float	0.0	The viscosity error tolerance
use_multigrid_acceleration	Bool	True	Enable a method that greatly increases the quality of the pressure channe. Keep enabled unless you experience artifacts or stability issues
cfl_min_steps	Int	1	The minimum number of simulation steps per frame
cfl_max_steps	Int	1	The maximum number of simulation steps per frame
dt_scale	Float	1.0	Time scaling constant. 2.0 means time flows 2x faster than normal
dens_dissipation	Float	0.0	The rate by which smoke dissipates
dens_dissipation_low_thresh	Float	0.0	Smoke density threshold below which dissipation increases rapidly
dens_dissipation_low_rate_gain	Float	4.0	Multiplier on the rate of non-linear dissipation below the threshold density
use_vorticity_confinement	Bool	True	Enable a method that adds energy to vortices in the simulation
vorticity_confinement	Float	2.0	Determines the amount of energy added to the vortices
vorticity_confinement_adaptive	Bool	True	Enables a method that only injects energy into relevant regions of the simulation
vorticity_confinement_scale_energy_falloff_power	Float	1.0	Controls the distribution of the size of the features targeted by the adaptivity method. Higher values more strongly emphasises high frequencies
vorticity_confinement_adaptive_tolerance	Float	0.3	Threshold determining how aggressively the adaptivity oracle selects valid regions for energy injection
use_wavelet_turbulence	Bool	True	Enables an algorithm that synthesizes additional turbulence adding visual complexity to the simulation
wavelet_turbulence_strength	Float	30.0	Controls the magnitude of the synthesized turbulence
wavelet_turbulence_scale_energy_falloff_power	Float	3.0	Controls the distribution of the size of the features targeted by the adaptivity method. Higher values more strongly emphasises high frequencies
wavelet_turbulence_adaptive_tolerance	Float	0.1	Threshold determining how aggressively the turbulence adaptivity oracle selects valid regions for turbulence injection
channel_list	ChannelList		Allows specification of channel meta data like interpolation or transformation mode

Input plugs	Type	Description
density	Emitter (array, optional)	An emitter for the density channel.
velocity	Emitter (array, optional)	An emitter for the velocity channel.
colliders	Collider (array, optional)	The collision objects for the simulation.
bounds	Box3f (optional)	Bounding box that constrains the expansion of the simulation.

Output plugs	Type	Description
element	SparseVolumeChannelSet	The ChannelSet containing the simulated fields.

Rendering nodes

Render

Performs a render and returns the resulting image.

Properties	Type	Default	Description
width	Int	640	Width of the rendered image in pixels.
height	Int	480	Height of the rendered image in pixels.

Input plugs	Type	Description
render_data	RenderData	The data describing the render.

Output plugs	Type	Description
image	Image	The rendered image.
image_generator	ImageGenerator	An ImageGenerator for the rendered image.

RenderData

Combines all the data needed for a render.

Properties	Type	Default	Description
max_progressions	Int	200	The maximum number of samples to use for each pixel
error_bound	Float	0.0	The allowed error in the color value of each pixel. Once the pixel color has been determined to within this accuracy, no further samples will be taken by this pixel.
multiple_scattering	Bool	False	Enables multiple scattering calculations by casting secondary rays
enable_motion_blur	Bool	False	Enables rendering of motion blur
shutter_mode	String	“Forward”	The shutter mode for motion blur calculations. See Camera shutter modes for the available modes.
shutter_angle	Float	180.0	The shutter angle controls the amount of motion blur, measured in degrees
deep_sample_scale	Float	4.0	Scale for the size the deep sample depths, measured as a multiple of the voxel size
max_deep_samples_per_pixel	Int	128	Maximum number of deep samples that can be created for each pixel
camera_projection	String	“Perspective”	The type of camera projection to use for the render. See Camera projection types for the available types.
window_translate	V2f	[0.0, 0.0]	The rendering window translation, in space where window extends from (-1,-1) to (1,1), this affects only the rendered image and not the actual camera.
window_scale	V2f	[1.0, 1.0]	The rendering window scale transformation, this affects only the rendered image and not the actual camera.
window_roll	Float	0.0	The rendering window roll rotation, in radians, this affects only the rendered image and not the actual camera.
custom_volume_settings	Bool	False	Specify render settings manually instead of automatically selecting them by analyzing the volume
volume_integrator_type	String	“Raymarching”	The type of integrator to use for primary rays. See Integrator types for the available types.
volume_transmittance_integrator_type	String	“Raymarching”	The type of integrator to use for primary transmittance rays. See Transmittance integrator types for the available types.
volume_secondary_integrator_type	String	“Raymarching”	The type of integrator to use for secondary rays. See Integrator types for the available types.
volume_secondary_transmittance_integrator_type	String	“Raymarching”	The type of integrator to use for secondary transmittance rays. See Transmittance integrator types for the available types.
volume_monochrome_extinction	Bool	False	Indicates that the volume only contains monochrome extinction. If this is set incorrectly, the rendered result will be incorrect.
volume_enable_supervoxels	Bool	False	Enables supervoxels to potentially speed up rendering
volume_equiangular_sampling	Bool	False	Enables equi-angular sampling in the integrators. See Equi-angular sampling.
volume_thin_media_sampling	Bool	False	Enables thin media sampling for the tracking integrator. See ThinMediaLabel.
volume_raymarch_step_scale	Float	1.0	Scale which increases the step size used by the raymarching integrators. Increasing the step size will be faster, but results will not be accurate.
volume_raymarch_transmittance_step_scale	Float	1.0	Scale which increases the step size used by the raymarching transmittance integrators. Increasing the step size will be faster, but results will not be accurate.

Input plugs	Type	Description
scene	RenderScene	The scene to be rendered.
camera	Camera	The camera to use for rendering the scene.

Output plugs	Type	Description
render_data	RenderData	The data describing the render. This can be passed to the Render node, or to an API function to manually control the progress of the render.

RenderScene

Describes a scene to be rendered.

Properties	Type	Default	Description
ambient_light	V3f	[0.0, 0.0, 0.0]	The ambient light for the scene. This is equivalent to an environment light with a constant value, so still requires shadow rays.
background_colour	V3f	[0.0, 0.0, 0.0]	The color returned by rays which do not hit any objects in the scene.

Input plugs	Type	Description
render_volume	RenderVolume (optional)	A volume to be rendered.
point_lights	PointLight (array, optional)	The point lights to use in the scene.
spot_lights	SpotLight (array, optional)	The spotlights to use in the scene.
quad_area_lights	QuadAreaLight (array, optional)	The quad area lights to use in the scene.
directional_lights	DirectionalLight (array, optional)	The directional lights to use in the scene.
environment_lights	EnvironmentLight (array, optional)	The environment lights to use in the scene.
holdouts	Holdout (array, optional)	The holdout objects to render.

Output plugs	Type	Description
scene	RenderScene	The scene data, can be passed to the RenderData node.

Holdout

A holdout object which can be placed in the RenderScene and will block rays. Can be either a mesh or a signed-distance field.

Properties	Type	Default	Description
primary_visible	Bool	True	Controls if the holdout will be hit by primary (camera) rays
mesh	CompoundMesh		A mesh to use as a holdout object.

Input plugs	Type	Description
field	Field (Scalar, optional)	A signed-distance field to use as a holdout object.

Output plugs	Type	Description
holdout	Holdout	The holdout data, can be passed to the RenderScene node.

DirectionalLight

Creates a directional light for a RenderScene.

Properties	Type	Default	Description
direction	V3f	[1.0, 0.0, 0.0]	Direction from which the light is coming.
intensity	V3f	[1.0, 1.0, 1.0]	Intensity of the light.
light_groups	Int	0	Flags indicating to which groups this light belongs.

Output plugs	Type	Description
light	DirectionalLight	The light data, can be passed to the RenderScene node.

EnvironmentLight

Creates an environment light for a RenderScene, based on an environment map image.

Properties	Type	Default	Description
image	Image		The environment map image.
transform	M44f	Identity	Transform to apply to the environment map.
intensity	V3f	[1.0, 1.0, 1.0]	Intensity of the light. This will scale the values in the environment map image.
light_groups	Int	0	Flags indicating to which groups this light belongs.

Output plugs	Type	Description
light	EnvironmentLight	The light data, can be passed to the RenderScene node.

PointLight

Creates a point light for a RenderScene.

Properties	Type	Default	Description
transform	M44f	Identity	Transform of the light in world space.
intensity	V3f	[1.0, 1.0, 1.0]	Intensity of the light.
falloff	String	“None”	Fall-off behavior of the light. See Light falloff modes for the available modes.
light_groups	Int	0	Flags indicating to which groups this light belongs.

Output plugs	Type	Description
light	PointLight	The light data, can be passed to the RenderScene node.

QuadAreaLight

Creates a quadrilateral area light for a RenderScene.

Properties	Type	Default	Description
transform	M44f	Identity	Transform of the light in world space.
intensity	V3f	[1.0, 1.0, 1.0]	Intensity of the light.
falloff	String	“None”	Fall-off behavior of the light. See Light falloff modes for the available modes.
light_groups	Int	0	Flags indicating to which groups this light belongs.

Output plugs	Type	Description
light	QuadAreaLight	The light data, can be passed to the RenderScene node.

SpotLight

Creates a spotlight for a RenderScene.

Properties	Type	Default	Description
transform	M44f	Identity	Transform of the light in world space.
intensity	V3f	[1.0, 1.0, 1.0]	Intensity of the light.
inner_falloff	Float	90.0	The inner angle of the spotlight falloff cone, in degrees.
outer_falloff	Float	90.0	The outer angle of the spotlight falloff cone, in degrees.
falloff	String	“None”	Fall-off behavior of the light. See Light falloff modes for the available modes.
light_groups	Int	0	Flags indicating to which groups this light belongs.

Output plugs	Type	Description
light	SpotLight	The light data, can be passed to the RenderScene node.

Denoiser

Denoises an image.

Properties	Type	Default	Description
hdr	Bool	True	Specifies if the input image is high dynamic range.

Input plugs	Type	Description
image	Image	The source image to be denoised.

Output plugs	Type	Description
image	Image	The resulting denoised image.

Render Volume nodes

FireRenderVolume

Creates a renderable volume based on input fields, using a black body spectrum for emission based on a temperature field. The absorption and scattering coefficients are specified directly.

Properties	Type	Default	Description
absorption_coefficient	Float	1.0	The absorption coefficient controls how much light is absorbed without being scattered per unit of distance
absorption_colour	Color3f	[1.0, 1.0, 1.0]	Color multiplier for the absorption coefficient, allowing absorption to be different for each color channel
scattering_coefficient	Float	1.0	The scattering coefficient controls how much light is scattered, for both in-scattering and out-scattering, per unit of distance
scattering_colour	Color3f	[1.0, 1.0, 1.0]	Color multiplier for the scattering coefficient, allowing scattering to be different for each color channel
emission_coefficient	Float	1.0	Scale applied to the emission values generated by the black body settings
emission_exposure	Float	20.0	An exposure type scale applied to the emission values generated by the black body settings
temperature_coefficient	Float	1.0	Scale applied to the input temperature field before converting temperature to emission using the black body model
black_body_white_balance	Float	2700.0	Specifies the temerature value which will map to a white emission color
color_space	String	“sRGB”	Specifies the color space in which the black body emission should be produced
black_body_min_temperature	Float	200.0	Specifies the minimum temperature for which to calculate a black body emission color. Temperatures below this will be clamped to this value.
black_body_max_temperature	Float	5000.0	Specifies the maximum temperature for which to calcualte a black body emission color. Temperatures above this will be clamped to this value.
phase_function_type	String	“isotropic”	The type of phase function to use for scattering in the volume
phase_function_parameter	Float	0.2	Controls the amount and direction of scattering by the phase function. Must be between -1 and 1. Positive values are forward scattering, negative values are backward scattering.
min_feature_size	Float	0.0	Optionally specifies the feature size for implicit volumes, to allow raymarching integrators to be used. Use with care, it can always be left at zero to avoid any issues.
black_body_num_samples	Int	1024

Input plugs	Type	Description
density	Field (Scalar, optional)	A field specifying the density of the smoke.
velocity	Field (Vector, optional)	A field for the fluid velocity.
temperature	Field (Scalar, optional)	A field specifying the temperature of the fire.
holdout	Field (Vector, optional)	A field describing an extinction based holdout.
channel_set	ChannelSet (optional)	A ChannelSet containing the fields, which will be used if the corresponding field plug is not connected.

Output plugs	Type	Description
render_volume	RenderVolume	The renderable volume, can be passed to RenderScene.

FireAlbedoRenderVolume

Creates a renderable volume based on input fields, using a black body spectrum for emission based on a temperature field. The albedo is used to describe the absorption and scattering.

Properties	Type	Default	Description
scattering_albedo	Float	0.7	The scattering albedo determines how much of the extinction is due to scattering or absorption. A value of 0.0 is fully absorbing, a value of 1.0 is fully scattering.
extinction_coefficient	Float	1.0	The extinction coefficient controls how much light is absorbed or scattered per unit of distance
scattering_colour	Color3f	[1.0, 1.0, 1.0]	Color multiplier for the scattering coefficient, allowing scattering to be different for each color channel
extinction_colour	Color3f	[1.0, 1.0, 1.0]	Color multiplier for the extinction coefficient, allowing extinction to be different for each color channel
emission_coefficient	Float	1.0	Scale applied to the emission values generated by the black body settings
emission_exposure	Float	20.0	An exposure type scale applied to the emission values generated by the black body settings
temperature_coefficient	Float	1.0	Scale applied to the input temperature field before converting temperature to emission using the black body model
black_body_white_balance	Float	2700.0	Specifies the temerature value which will map to a white emission color
color_space	String	“sRGB”	Specifies the color space in which the black body emission should be produced
black_body_min_temperature	Float	200.0	Specifies the minimum temperature for which to calculate a black body emission color. Temperatures below this will be clamped to this value.
black_body_max_temperature	Float	5000.0	Specifies the maximum temperature for which to calcualte a black body emission color. Temperatures above this will be clamped to this value.
phase_function_type	String	“isotropic”	The type of phase function to use for scattering in the volume
phase_function_parameter	Float	0.2	Controls the amount and direction of scattering by the phase function. Must be between -1 and 1. Positive values are forward scattering, negative values are backward scattering.
min_feature_size	Float	0.0	Optionally specifies the feature size for implicit volumes, to allow raymarching integrators to be used. Use with care, it can always be left at zero to avoid any issues.
black_body_num_samples	Int	1024

Input plugs	Type	Description
density	Field (Scalar, optional)	A field specifying the density of the smoke.
velocity	Field (Vector, optional)	A field for the fluid velocity.
temperature	Field (Scalar, optional)	A field specifying the temperature of the fire.
holdout	Field (Vector, optional)	A field describing an extinction based holdout.
channel_set	ChannelSet (optional)	A ChannelSet containing the fields, which will be used if the corresponding field plug is not connected.

Output plugs	Type	Description
render_volume	RenderVolume	The renderable volume, can be passed to RenderScene.

SmokeRenderVolume

Creates a renderable volume based on input fields. The absorption and scattering coefficients are specified directly.

Properties	Type	Default	Description
absorption_coefficient	Float	1.0	The absorption coefficient controls how much light is absorbed without being scattered per unit of distance
absorption_colour	Color3f	[1.0, 1.0, 1.0]	Color multiplier for the absorption coefficient, allowing absorption to be different for each color channel
scattering_coefficient	Float	1.0	The scattering coefficient controls how much light is scattered, for both in-scattering and out-scattering, per unit of distance
scattering_colour	Color3f	[1.0, 1.0, 1.0]	Color multiplier for the scattering coefficient, allowing scattering to be different for each color channel
phase_function_type	String	“isotropic”	The type of phase function to use for scattering in the volume
phase_function_parameter	Float	0.2	Controls the amount and direction of scattering by the phase function. Must be between -1 and 1. Positive values are forward scattering, negative values are backward scattering.
min_feature_size	Float	0.0	Optionally specifies the feature size for implicit volumes, to allow raymarching integrators to be used. Use with care, it can always be left at zero to avoid any issues.

Input plugs	Type	Description
density	Field (Scalar, optional)	A field specifying the density of the smoke.
velocity	Field (Vector, optional)	A field for the fluid velocity.
emission	Field (Vector, optional)	A field specifying the emission directly.
holdout	Field (Vector, optional)	A field describing an extinction based holdout.
channel_set	ChannelSet (optional)	A ChannelSet containing the fields, which will be used if the corresponding field plug is not connected.

Output plugs	Type	Description
render_volume	RenderVolume	The renderable volume, can be passed to RenderScene.

SmokeAlbedoRenderVolume

Creates a renderable volume based on input fields. The albedo is used to describe the absorption and scattering.

Properties	Type	Default	Description
scattering_albedo	Float	0.7	The scattering albedo determines how much of the extinction is due to scattering or absorption. A value of 0.0 is fully absorbing, a value of 1.0 is fully scattering.
extinction_coefficient	Float	1.0	The extinction coefficient controls how much light is absorbed or scattered per unit of distance
scattering_colour	Color3f	[1.0, 1.0, 1.0]	Color multiplier for the scattering coefficient, allowing scattering to be different for each color channel
extinction_colour	Color3f	[1.0, 1.0, 1.0]	Color multiplier for the extinction coefficient, allowing extinction to be different for each color channel
phase_function_type	String	“isotropic”	The type of phase function to use for scattering in the volume
phase_function_parameter	Float	0.2	Controls the amount and direction of scattering by the phase function. Must be between -1 and 1. Positive values are forward scattering, negative values are backward scattering.
min_feature_size	Float	0.0	Optionally specifies the feature size for implicit volumes, to allow raymarching integrators to be used. Use with care, it can always be left at zero to avoid any issues.

Input plugs	Type	Description
density	Field (Scalar, optional)	A field specifying the density of the smoke.
velocity	Field (Vector, optional)	A field for the fluid velocity.
emission	Field (Vector, optional)	A field specifying the emission directly.
holdout	Field (Vector, optional)	A field describing an extinction based holdout.
channel_set	ChannelSet (optional)	A ChannelSet containing the fields, which will be used if the corresponding field plug is not connected.

Output plugs	Type	Description
render_volume	RenderVolume	The renderable volume, can be passed to RenderScene.

ExpressionRenderVolume

Creates a renderable volume using an expression script to provide the data needed for rendering.

Properties	Type	Default	Description
language	String	“Python”	The language to use for the shader expression
expression_python	String		Python script for the shader expression
expression_cpp	String		C++ script for the shader expression
phase_function_type	String	“isotropic”	The type of phase function to use for scattering in the volume
phase_function_parameter	Float	0.2	Controls the amount and direction of scattering by the phase function. Must be between -1 and 1. Positive values are forward scattering, negative values are backward scattering.
min_feature_size	Float	0.0	Optionally specifies the feature size for implicit volumes, to allow raymarching integrators to be used. Use with care, it can always be left at zero to avoid any issues.
bounds_field	String		Name of the field from which to take the volume bounds. Not used if explicit bounds are provided

Input plugs	Type	Description
bounds	Box3f (optional)	Directly specifies the bounds of the volume.

Output plugs	Type	Description
render_volume	RenderVolume	The renderable volume, can be passed to RenderScene.