Flow Block End Copernicus node

End of a Flow simulation block.

On this page	Parameters Caching Pressure Projection Inputs Outputs
Since	21.0

This node marks the end of a Flow simulation block.

It should be paired with a Flow Block Begin COP.

Note

Compiled COP networks don’t support simulation.

Parameters ¶

Simulate

While Flow will always need to feedback to do anything interesting, it can either work in a simulation mode where it feeds back over time; or for each frame run a set number of steps independently.

Time Scale

Control the size of the timestep within the simulation.

Iterations

When simulation is off, this controls the number of steps the solver will run in an evaluation.

Substeps

When simulation is on, each frame will be broken into this number of substeps. Substeps allow for more accurate behaviour, but might also increase diffusion.

Reset Simulation

When Simulate is on, this clears the entire simulation cache.

Start Frame

When Simulate is on, this is the frame on the Houdini playbar where the simulation starts.

Live Simulation

When Simulate is on, this turns on live simulation to provide an interactive, non-deterministic simulation mode. It simulates independent of the playbar and isn’t associated with any keyframes or caching.

This parameter (and its associated parameters) is intended as a sandbox mode where you don’t have to rely on the playbar.

Tip

Live Simulation doesn’t save the results like other simulation types in Houdini, so use a Stash COP to save results.

Toggle Live Simulation

When Live Simulation is on, this lets you pause and resume the live simulation.

Tip

You can also use the Live Simulation button to pause and resume live simulation. See Cooking controls for more information.

Live Tick

When Live Simulation is on, this is the current tick (frame) within the live simulation.

Caching ¶

Cache Simulation

When Simulate is on, this enables the caching of the simulation. If the simulation is uncached, it will always have to cook from the start frame on any new frame.

Cached Frames

When Simulate is on, this is how many frames behind the current frame to keep cached.

Checkpoint Rate

When Simulate is on, this is the rate at which the node continually caches a single frame.

For example, set this to 24 to cache frames 24, 48, 72, and such. This allows random-scrubbing to be faster as it only has to re-cook from the checkpoint frame.

Set to 0 to disable checkpointing.

Pressure Projection ¶

Collision Iterations

Number of collision iterations to perform. Higher iterations will result in better avoidance of the collision object, but will increase execution times.

Multigrid Iterations

Number of multigrid iterations to perform. Higher iterations will result in matching the goal divergence better, but will increase execution times.

X Border

State of borders on the left and right sides of the image. Open borders allow flow to leave the image’s bounds without resistance. Closed borders act like solid walls. When set to Periodic, flow leaving through the right side re-enters on the left side (and vice versa).

Y Border

State of borders on the bottom and top sides of the image. Open borders allow flow to leave the image’s bounds without resistance. Closed borders act like solid walls. When set to Periodic, flow leaving throgh the top side re-enters on the bottom side (and vice versa).

Inputs ¶

color

An RGBA layer of the current fluid colors, fedback to the input.

A UV layer of the flow velocities, fedback to the input.

temperature

A Mono layer of the current fluid temperatures, fedback to the input.

feedback

A Cable of the current feedback data. This is fedback to the input. The structure of this cable must match the initial structure provided on the block begin.

divergence

An optional Mono layer providing a goal divergence for the velocity, allowing the fluid to expand or contract.

collision

An optional Mono layer providing a mask of the collider. Values of 1 will act like colliders.

collisionv

An optional UV layer providing the velocities of the collider.

Outputs ¶

color

An RGBA layer of the current color values.

A UV layer of the current flow velocities.

temperature

A Mono layer of the current fluid temperature.

feedback

A Cable of the current feedback data.

See also

Flow Block Begin

Copernicus nodes

Auto Stereogram

Generates an image with a 3D illusion.
Bake Geometry Textures

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

Curves images using handles or a captured region.
Blend

Blends two layers together.
Block Begin

Start of a block, containing its inputs.
Block End

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

Compiles a block and produces its geometry representation.
Blur

Applies a blur to a layer.
Bokeh

Creates a Bokeh effect by expanding each pixel by an aperture shape.
Bounding Rectangle

Finds the bounding rectangle of a mask.
Bright

Brightens a layer.
Bubble Noise

Generates bubble noise.
Cable Filter

Removes empty wires from a cable.
Cable Merge

Combines two cables into one cable.
Cable Pack

Combines input layers into a cable.
Cable Rename

Renames a cable’s wires based on filters.
Cable Sort

Sorts a cable’s wires by name.
Cable Split

Splits a cable based on filtering parameters.
Cable Switch

Selects an input cable.
Cable Unpack

Extracts individual wires from a cable.
Cache

Caches the input layers for faster playback.
Camera Import

Creates a layer in a camera’s space.
Camera Properties

Adjusts the camera properties of a layer.
Channel Extract

Extracts a channel from a layer.
Channel Join

Combines multiple Mono layers into one multichannel layer.
Channel Split

Divides a layer’s channels into Mono layers.
Channel Swap

Swaps channels within a multichannel layer.
Checkerboard

Creates an alternating checker pattern.
Chladni Cymatic Patterns

Generates interference patterns that represent various vibration modes.
Chroma Key

Keys an input based on hue, saturation, and luminance ranges.
Chromatic Aberration

Adds chromatic aberration to your image.
Clamp

Clamps an input layer.
Cloud Noise 3D

Generates a billowy cloud noise.
Color Correct

Adjusts colors in the image.
Combine Layers

Combines all input layers.
Combine Normals

Blends two normal maps together.
Compare

Creates a mask by comparing two layers.
Constant

Initializes pixels to constant values.
Contact Sheet

Arranges input layers into a contact sheet.
Contrast

Applies contrast to a layer.
Convert Depth

Converts depth layers between height, depth, and distance.
Convert Normal

Converts normal layers between signed and offset.
Convolve 3×3

Convolves a layer by a 3×3 kernel.
Copy and Transform

Copies stamps and applies transformations to the copies.
Corner Pin

Pins a layer’s corners in a reference layer.
Crop

Crops a layer to a new size.
Cross Product

Performs a cross product of two RGB layers.
Cryptomatte

Builds a matte from cryptomatte layers.
Cryptomatte Decode

Decodes a cyrptomatte into coverage and ID.
Cryptomatte Encode

Encodes a coverage and object hash into a cryptomatte layer.
Crystal Noise

Generates a sharp and angular Worley noise type.
Curvature

Computes the curvature of a layer.
Curve 3D

Lets you interactively draw Bézier curves using tools similar to 2D illustration programs, as well as polylines and NURBS.
Defocus

Defocuses an input layer.
Denoise AI

Denoises an input layer.
Denoise TVD

Removes white noise from an image.
Derivative

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

Dilates or erodes a layer.
Distort

Distorts an input layer.
Dot Product

Performs dot product between two layers.
Edge Detect

Detects edges in the input image.
Edge Detect by Contour

Detects varying-width silhouette lines.
Edge Detect by Depth

Detects varying-width self-occluding silhouettes.
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.
Flow Project Non-Divergent Multigrid

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

Creates a point for each leaf of a VDB that would be in an envelope.
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

Captures images from a live video source.
Mask from Curves

Creates a mask from 2D curves.
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.
Pyro Advect

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.
Pyro Dissipate

Dissipates a VDB’s values over time.
Pyro Disturbance

Applies disturbance to a velocity VDB to break up still air.
Pyro Light Ambient

Builds a light field of ambient illumination of a VDB.
Pyro Light Scatter

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

Builds a light field of points lighting a VDB.
Pyro Packed MipMap

Builds an in-place MipMap of a VDB.
Pyro Project Non-Divergent Electro Static

Removes divergence from a velocity VDB.
Pyro Source from Layer

Sources from a layer’s envelope into a VDB.
Pyro Source from Points

Sources points into a VDB.
Pyro Turbulence

Apply turbulence to a velocity VDB.
Pyro Uniform Force

Applies a uniform force.
Python Snippet

Runs a snippet of Python on layers.
Quantize

Quantizes input data into discrete steps.
RGB to RGBA

Converts RGB layers to RGBA.
RGB to UV

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

Converts RGBA layers to RGB.
RGBA to UV

Splits an RGBA layer into two UV layers.
ROP Image

Writes the output of a COP network to disk.
Ramp

Generates linear and radial ramps.
Random Mono

Creates a mono layer with random values.
Random RGB

Creates an RGB layer with random colors.
Rasterize Curves

Rasterizes curves onto a layer.
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

Renders a volume viewed through a camera
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

Blends multiple image inputs by a blend factor.
Sharpen

Sharpens an input layer to increase the definition of its edges.
Slap Comp Import

Import live layers from the Solaris Viewport.
Slope Direction

Converts a height layer into a direction layer.
Smooth Fill

Smoothly fills a region of a layer.
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

Darkens the corners of an input layer.
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.