Pyro Activate Copernicus node

Changes the activation of VDBs in a Pyro simulation.

On this page	Parameters Inputs Outputs
Since	21.0

This node will update the activation of voxels in the VDBs of a Pyro simulation. The solve only occurs where the voxels are active, so it is important to keep both the volume to be solved active, but also enough of a buffer so the surrounding air field will be present.

The VDB Visualize Tree COP can be used to inspect what regions are activated.

Activation is done at the “leaf” level, which are blocks of 8×8×8 voxels.

The fewer the active leaves, the less memory and the faster the simulation runs.

Parameters ¶

Density Cutoff

Any leaf whose maximum density is below the cutoff will be eligible to be deactivated.

Leaf Dilation

Expand the active region a fixed number of leaves.

The maximum of Leaf Dilation Dist and Leaf Dilation are used.

Leaf Dilation Dist

Expand the active region a fixed distance in world space; this is raised to the nearest leaf.

The maximum of Leaf Dilation Dist and Leaf Dilation are used.

Velocity Dilation

Each leaf’s maximum velocity in each of the directions is measured, and the leaf expanded to cover that distance.

This can ensure the air field is present for the incoming air.

Velocity Scale

Scale the velocity used for velocity dilation. This also scaled by the timestep.

Tangential Scale

Also dilate in the perpendicular directions to the velocity by this portion of the velocity dilation. Usually fluid is turbulent, so if it needs to extend in one direction the neighboring directions are also likely important.

Ambient Velocity

A global constant velocity term to add to all the velocities for the purpose of dilation. This is important to match any ambient velocity on the advection.

Clip Min X

Deactivate any leaves with world positions less than this in X.

Clip Min Y

Deactivate any leaves with world positions less than this in Y.

Clip Min Z

Deactivate any leaves with world positions less than this in Z.

Clip Max X

Deactivate any leaves with world positions greater than this in X.

Clip Max Y

Deactivate any leaves with world positions greater than this in Y.

Clip Max Z

Deactivate any leaves with world positions greater than this in Z.

Inputs ¶

density

A float VDB used both as the reference size for activation, and to provide the density values to cull inactive leaves.

A vector VDB providing the velocities for doing velocity dilation.

activate_pts

Additional points to activate with. Any leaf which contains the point will be activated.

Outputs ¶

float

A representative float VDB with leaves activated by the rules.

vector

A representative vector VDB with leaves activated by the rules.

See also

Copernicus nodes

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Bake Geometry Textures

Generates textures by baking between a low-resolution and high-resolution mesh at interactive speeds.
Bend

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Blend

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Block Begin

Start of a block, containing its inputs.
Block End

End of a block, declaring its outputs.
Block to Geometry

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Bokeh

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Cable Filter

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Cable Pack

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Camera Properties

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Channel Join

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Channel Split

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Channel Swap

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Color Correct

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Compare

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Copy and Transform

Copies stamps and applies transformations to the copies.
Corner Pin

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Crop

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Cross Product

Performs a cross product of two RGB layers.
Cryptomatte

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Cryptomatte Decode

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Cryptomatte Encode

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Crystal Noise

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Curvature

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Defocus

Defocuses an input layer.
Denoise AI

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Denoise TVD

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Derivative

Computes the derivative of the source layer along the x- and y-axis.
Dilate Erode

Dilates or erodes a layer.
Distort

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Dot Product

Performs dot product between two layers.
Edge Detect

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Edge Detect by Contour

Detects varying-width silhouette lines.
Edge Detect by Depth

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Edge Detect by Normal

Detects varying-width crease-lines.
Eikonal

Computes distances by solving the Eikonal equation.
Equalize

Equalizes colors by stretching or shifting their range.
Error

Generates a message, warning, or error.
Extrapolate Boundaries

Fills empty areas of an image using colors at the edges of non-empty areas.
Feather

Smooths out sharp changes in contrast.
Fetch

Brings a COP node’s outputs into the current network.
File

Loads an image or video from disk.
Fill

Fills a layer with a constant value.
Fill Connected

Flood fills the connected regions of a layer.
Flip

Flips a layer horizontally, vertically, or diagonally.
Flow Block Begin

Start of a Flow simulation block.
Flow Block End

End of a Flow simulation block.
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Removes divergent components from a 2-dimensional vector field.
Font

Rasterizes text onto a layer from Type 1, TrueType, and OpenType fonts.
Fractal Noise

Generates fractal noise.
Fractal Noise 3D

Generates fractal noise from 3D locations.
Function

Applies a mathematical function to a layer.
Gamma

Applies gamma correction to a layer.
Geometry to Layer

Converts a volume into a layer.
Glow

Adds glow to an image based on its luminance.
HSV Adjust

Converts between RGB and HSV color spaces, or modifies HSV.
Heat Distort

Distorts the input layer to simulate heat around fire and other mirage effects.
Heat Distort by Layer

Distorts the input layer using another layer to simulate heat around fire and other mirage effects.
Height to Ambient Occlusion

Imagines a sphere for each pixel and determines how occluded that sphere is based on its surroundings.
Height to Normal

Converts a height layer to a normal layer.
Height to Shadow

Creates shadows using a virtual light source.
HeightField Visualize

Visualizes layers as colored heightfields.
Hex Tile

Randomly tiles texture.
Histogram

Builds a histogram from a layer.
Hyperbolic Tile

Generates hyperbolic polygon tiles for texture patterns.
ID to Mask

Creates a mask from an ID layer based on filtering parameters.
ID to Mono

Converts an ID layer into a mono layer.
ID to RGB

Converts an ID layer into an RGB layer.
ID to SDF

Computes a Signed Distance Field from changes in ID values.
Illegal Pixel

Detects and then fixes or highlights illegal pixels in images.
Input

Fetches the input to a subnetwork.
Integrate Volume

Simple integration of a VDB along camera rays.
Invert

Inverts a layer.
Invoke Block

Runs a block using inputs plugged into this node.
Invoke Geometry

Runs a program saved into geometry using inputs plugged into this node.
Julia Fractal

Computes the Julia set to create a fractal.
Kuwahara Filter

Applies the Kuwahara filter, which creates painterly effects.
Lattice Deform

Applies grid-based deformation to a layer.
Layer

Generates a layer.
Layer Attribute Create

Adds or edits user-defined metadata on a layer.
Layer Attribute Delete

Removes user-defined metadata from a layer.
Layer Properties

Edits basic layer metadata.
Layer from Curves

Render Curves into a Layer.
Layer from VDB

Sets a layer’s values from a VDB.
Layer to Geometry

Converts a layer into a 2D volume.
Layer to Points

Creates points based on a layer.
Layer to VDB Leaf Points

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Lens Distort

Adds radial and tangential distortion to a layer based on OpenCV coefficients.
Light

Lights a layer given a light direction and normals.
Live Video

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Mask from Curves

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Match Camera

Transforms a layer to match a reference camera.
Match UDIM

Reframes pixels of a layer to match a particular UDIM tile.
Median

Applies a median filter to an image.
Mirror

Mirrors an image based on an arbitrary number of planes.
Mono

Converts a layer to mono.
Mono to ID

Converts a mono layer into an ID layer.
Mono to RGB

Converts a mono layer into an RGB layer.
Mono to RGBA

Converts a mono layer into an RGBA layer.
Mono to SDF

Computes a signed distance field from an iso-level of a mono layer.
Null

Passes inputs to the outputs.
OCIO Transform

Converts color spaces using OCIO transforms.
ONNX Inference

Applies inference from an ONNX Machine Learning model.
OpenCL

Executes an OpenCL kernel on layers, attributes, volumes, and VDBs.
Output

Collects the outputs of a subnetwork.
Phasor Noise

Generates phasor noise, which resembles a wave pattern.
Pixelate

Increases the size of pixels to pixelate an input layer.
Polar to UV

Converts polar coordinate pixels to Cartesian pixels.
Position Map

Generates a position map.
Position Sample

Samples an input texture by position.
Prefix Sum

Computes the prefix sum of a layer.
Premultiply

Premultiplies or un-premultiplies an RGBA layer.
Preview Material

Applies the preview material to geometry.
Project on Layer

Projects a layer onto a target layer.
Pyro Activate

Changes the activation of VDBs in a Pyro simulation.
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Advects VDBs by Velocity.
Pyro Advect by Map

Advects a VDB by a flow map.
Pyro Axis Force

Applies a force around an axis to a velocity VDB.
Pyro Block Begin

Start of a Pyro simulation block.
Pyro Block End

End of a Pyro simulation block.
Pyro Build Advection Map

Constructs a flow map from a velocity VDB.
Pyro Buoyancy

Applies a Buoyancy force.
Pyro Configure

Configures a Pyro simulation.
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Pyro Disturbance

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Builds a light field of internal glow of a VDB.
Pyro Light from Points

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Pyro Packed MipMap

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Removes divergence from a velocity VDB.
Pyro Source from Layer

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Pyro Source from Points

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Pyro Turbulence

Apply turbulence to a velocity VDB.
Pyro Uniform Force

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Python Snippet

Runs a snippet of Python on layers.
Quantize

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RGB to RGBA

Converts RGB layers to RGBA.
RGB to UV

Splits an RGB layer into UV and mono layers.
RGBA to RGB

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RGBA to UV

Splits an RGBA layer into two UV layers.
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Ramp

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Random Mono

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Random RGB

Creates an RGB layer with random colors.
Rasterize Curves

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Rasterize Geometry

Rasterizes geometry onto a layer.
Rasterize Layer

Rasterizes a layer onto another layer’s camera.
Rasterize Setup

Prepares geometry for the Rasterize Geometry COP.
Rasterize Volume

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Ray Trace

Performs ray tracing on an input mesh based on an origins and directions map.
Reaction-Diffusion Block Begin

Start of a Reaction-Diffusion simulation block.
Reaction-Diffusion Block End

Creates unique patterns by solving the reaction and diffusion of multiple chemicals as described by its inputs and parameters.
Remap

Remaps a layer.
Resample

Performs image scaling by changing the width, height, and pixel sizes.
SDF Adjust

Modifies the values for a Mono SDF layer.
SDF Blend

Combines two Mono SDF layers.
SDF Shape

Builds a 2D signed distance field of a selected shape.
SDF to Mono

Converts an SDF field to a Mono image layer.
SDF to RGB

Converts an SDF field to an RGB color layer.
SOP Import

Imports SOP geometry into Copernicus.
SOP Invoke

Invokes a compiled SOP block on the inputs.
SOP Invoke Graph

Invokes a geometry SOP graph on the inputs.
Scatter Shapes

Scatters input stamps across the image using randomization controls.
Scatter on Curves

Scatters input stamps along an input curve using randomization controls.
Segment by Connectivity

Segment a layer into connected components.
Segment by Value

Segment a mono layer into bands of similar value.
Sequence Blend

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Sharpen

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Slap Comp Import

Import live layers from the Solaris Viewport.
Slope Direction

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Smooth Fill

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Solve Poisson Multigrid

Solves Poisson’s equation in a rectangular region using geometric multigrid.
Space Transform

Transforms positions and UV values between spaces.
Stamp Points

Stamps layers from point positions.
Stash

Stashes the input of the node on command and uses it as the node’s output.
Statistics

Outputs the average, minimum and maximum values of the input layer
Statistics by ID

Compute statistics for each ID island.
Streak Blur

Streaks an image, adding a motion blur effect.
Subnetwork

Used to organize a collection of COPs into one node.
Surface Dither

Applies a halftone dithering pattern relative to UVs.
Swirl

Twists an image layer into a spiral shape.
Switch

Selects an input layer.
Switch If Wired

Selects an input based on what is connected.
Switch by Type

Selects an output layer by the type of the inputs.
Tile Pattern

Generates rectangular tiles for texture patterns.
Tone Map

Applies a filmic tone mapping curve to compress a high dynamic range input into a displayable range.
Transform 2D

Transforms a layer in 2D.
Transform 3D

Transforms a layer in 3D.
Triplanar

Generates a texture by projecting X, Y, and Z textures onto the position layer.
Triplanar Hex Tile

Seamless texturing and normal mapping of triplanar projections without visible repetitions.
Triplanar UV

Generates UVs in three orthogonal projections.
Two Way Switch If Wired

Selects between two inputs based on if you wire in another input.
UV Map

Generates a UV Map.
UV Map by ID

Creates a UV Map for each connected ID island.
UV Sample

Samples an input layer using a UV layer.
UV Transform

Transforms the values of a UV layer in 2d space.
UV to Polar

Converts Cartesian coordinate pixels to polar coordinate pixels.
UV to RGB

Joins a UV and mono layer into an RGB layer.
UV to RGBA

Joins two UV layers into an RGBA layer.
VDB Activate from Points

Activates leaves on a VDB according to a point cloud.
VDB Leaf Points

Creates a point for each active leaf in a VDB.
VDB Position Map

Stores in each voxel that voxel’s position.
VDB Reshape

Rebuilds a VDB to match another VDB’s topology.
VDB Visualize

Creates multi-volume visualization.
VDB Visualize Slice

Extracts a slice from a VDB as Geometry for visualization.
VDB Visualize Tree

Builds a geometry visualizing the topology of a VDB.
VDB Visualize Velocity

Traces streamers through a velocity VDB.
VDB from Layer

Sets VDB values from the closest values in a layer.
Vector Transform

Transforms values of an RGB layer in 3d space.
Vector Transform 2D

Transforms the values of a UV layer in 2D space.
Vignette

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Wipe

Performs a wipe transition between two images.
Worley Noise

Generates Worley noise.
Worley Noise 3D

Generates Worley noise from 3D locations.
Wrangle

Runs a VEX snippet to modify layer values.
Z Composite

Composites two layers by depth.