Houdini 21.0 Copernicus

Working with Copernicus nodes

Provides next steps and workflows for how to use Copernicus nodes.

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Viewing your output

You can view your Copernicus output in the Scene Viewer as a volume and Composite Viewer as an image. The output is a pixel representation of a voxel grid. Since some data is hard to visualize in the viewer, what the viewport displays isn’t always what’s in the data. Copernicus uses a default visualizer to enhance the visibility of the output. Height is visualized as heightfields in the Scene Viewer, and as hillshades in the Composite Viewer and preview thumbnail.

Tip

You can enter copcache -c in the textport window to clear your GPU and memory usage. This also recooks your scene if you have images displayed in your viewport. See copcache for more information about this HScript command.

In the Scene Viewer, there are two different levels where you can view your COP network output:

  • When viewing a node inside a COP network, the Scene View displays the first output of the COP node that has the display flag on.

    For nodes with multiple outputs, click the output name in the bottom right of the node to change which output appears in the viewer. This does not impact what outputs output in your SOP network.

    Tip

    You can also the node and choose the output name from the Flags ▸ Output for View drop-down menu.

  • When viewing a node inside the SOP network, the Scene View displays a SOP. When the COP Network node display flag is on, you're looking at a SOP that contains a COP network.

    For a COP node with the display flag on and multiple outputs in the COP network, you can use the COP Network node to control which output appears in the Scene View. In the COP Network node, turn on Single Output and then use Output to control which output appears in the Scene View. When Single Output is off, all outputs appear in the Scene View.

The Composite Viewer displays multiple views. For a COP node with the display flag on and multiple outputs in the COP network, you can use the main toolbar to choose from the output drop-down menu which output it displays.

Default COP Network settings

The Copernicus Default Settings window controls the global context options for Copernicus, which sets the default settings of the COP nodes. These control the default settings of COP nodes that don’t have their own input or values for these settings.

The COP Network and COP Network SOP can override some of the Copernicus Default Settings window’s settings. They control the default settings of COP nodes that don’t have their own input or settings. A node no longer uses these default settings if it has a node wired into it with values for these settings. If you unwire the nodes, the nodes return to their previous settings.

When you dive into the COP Network node, you can use the toolbar above your Copernicus network to view or change some of the following settings of the COP Network node.

  • Resolution

  • Pixel Scale (drives the Proxy 1:# parameter in the COP network toolbar)

    Note

    You can use the Proxy 1:# scale in the toolbar to cook the node resolution at a percentage of the scale. For example, turning on Proxy 1:2 cooks the nodes at half the resolution.

  • Border

  • Precision

  • Tile Visualization

    Note

    Replicates your input a set number of times. For example, set this to 3 to replicate your input three times. Tile Visualization is useful when you want to test whether your input properly tiles.

  • UDIM

Python states and handles

Copernicus Python states run in the Composite and Scene Views (see Python state Copernicus for more information). You can use the Operator Type Properties window to bind 2D and 3D handles to COP nodes.

See the following pages for some next steps:

COP nodes use the sidefx_transform2D handle. This handle works in the Scene Viewer (front and perspective viewports only) and in the Composite Viewer in a 2D coordinate system. It’s similar in functionality to the 3D Transform handle. The following are the possible handle modes.

  • Translate: The amount to move the X- or Y-coordinate from the origin. This value uses the space that the image is in.

  • Rotate: The amount in degrees to rotate the image around the Z-axis.

  • Scale: The amount to stretch the image along the X- or Y-axis. This value uses the space that the image is in.

  • Uniform Scale: The amount to stretch the image along the X-, Y-, and Z-axes. This value uses the space that the image is in.

Tip

  • For translate and rotate handles in detached mode (press the ' hotkey), you can position the handle independent from the node parameters. For example, drag the handle’s pivot center to offset the handle from the node’s origin.

  • To move handle gadgets in step mode, hold CTRL while you drag the handle.

  • To slow down the handle dragging speed, hold SHIFT while you drag the handle.

To...Do this

Enter states

In the Scene Viewer, press ENTER to enter states and ESC to exit them.

In the Composite Viewer, turn on the relevant node’s display flag to enter states and off to exit them.

Translate an image

Drag an arrow to move along an axis.

or

Drag the point at the center to move the image along both the X- and Y-axes.

Rotate an image

Drag a ring to rotate around an axis.

Scale an image

Drag a square to stretch an image along an axis. This is the Scale value.

or

Drag the point at the center to stretch the image along the X-, Y-, and Z-axes. This is the Uniform Scale value.

Edit the handle display

  1. Press P in the viewport. This opens the Parameters window.

  2. Click the Handle Dialog tab and expand the node with the handles you want to edit.

  3. Configure the handle settings. For example, set the Rotate Ring Style, Translate Pivot Style and Color, or turn off Translate Axes to hide them.

Use handle hotkeys

Press the following hotkeys in the viewport to change between the handle modes:

  • y: Cycle through the 3 modes.

  • ': Set the handle in detached mode. Toggle again to reattach it.

  • t: Set the handle to translate.

  • r: Set the handle to rotate.

  • e: Set the handle to scale.

Adding files from disk in COPs

The following steps outline how you add files from disk directly in your COP network.

  1. Create a File COP in your COP network.

  2. Set File Name to the image, MP4, or EXR file you want in your scene.

  3. For files with multiple AOVs, click Add AOVs from File to specify which AOVs to bring in.

  4. Configure the File COP further for the following:

    • For MP4 files, set the Video Start Frame to the frame number from where you want the video to start playing.

    • For EXR files, update $F# ($F4 for example) in the File Name to <F#> (<F4>). This lets you set the Video Start Frame to the frame number from where you want the sequence to start playing. $F# doesn’t use the Video Start Frame.

Saving COPs

The following procedures outline how to save COP nodes in your COP network. Most COP networks require the Multiple saves approach.

Multiple saves

Follow these steps if you plan to save a COP file in your network multiple times.

  1. Create an image output node in one of the following networks:

  2. Set COP Path to the node you want to save. In a COP network, a wire attaches the node to the ROP Image Output COP.

    Tip

    In a COP network, you can also drag the node you want to save into the COP Path parameter. The parameter adds the pathname.

  3. For nodes with multiple AOVs, click Add AOVs from COP to bring in all AOVs.

  4. Under File Layout, make sure that each Port is set to the node’s AOV port you want to save out.

Single save

Follow these steps if you plan to save a COP file in your network once. This saves the COP node from the current cook.

  1. the node you want to save in your COP network.

  2. Choose Image from the Save drop-down menu. The Save As window opens.

  3. Configure your saving details and click Save.

Note

In the Composite Viewer, you can also and choose Save Frame to open the Save As window.

Referencing COP networks

Copernicus lets you bring your COP network into other networks. You can reference other COP and SOP networks while working in a COP network. You can also reference your COP network while working in a SOP network.

Tip

If you want to reference a node that’s inside your COP network but don’t want to use it as an output, wire that node into a Null COP. You can then reference that Null COP’s path outside of the COP network. You must prefix the Null COP’s path with op: (for more information, see Use data from a node instead of a file (op:)).

Bringing COPs into COPs

Follow these steps to bring another COP’s results into your COP network.

  1. Create a Fetch COP in your COP network.

  2. Set COP Path to the path of a COP node in another network.

  3. Click Set Outputs from Selected COP. This pulls in the outputs from the target node, which become the outputs of the Fetch COP node.

Bringing SOPs into COPs

Follow these steps to bring a SOP network into your COP network.

  1. Create a SOP Import COP in your COP network.

  2. Configure the SOP Import COP to do one of the following:

    • Bring in an internal SOP.

      1. Dive into the SOP Import COP.

      2. Add and configure SOP nodes.

      3. Set the display flag on the SOP node you want to import.

    • Bring in an external SOP.

      1. Turn on Use External SOP.

      2. Set SOP Path to the path of a SOP node that’s outside of the COP network.

  3. If your SOP is a two-dimensional volume, do the following to turn it into a layer:

    1. Add a Geometry to Layer COP. Wire the SOP Import into this node.

    2. In the Geometry to Layer COP, set Signature to correspond to the volume’s type.

    Tip

    You can also use the Rasterize Geometry COP to take the piece of geometry and rasterize it into a layer. The node rasterizes the geometry based on the canonical camera unless you wire in a camera_ref input. To move the SOP back into view of the canonical camera, see Move SOP into image space.

Bringing COPs into SOPs

Follow these steps to bring a COP network into your SOP network.

  1. Create a COP Network SOP in your SOP network.

  2. Configure the COP Network SOP to do one of the following:

    • Bring in an internal COP.

      1. Dive into the COP Network SOP.

      2. Add and configure COP nodes.

      3. Set the display flag on the COP node you want to appear in the SOP network.

        Tip

        ⌃ Ctrl + a node’s display flag to turn on the 3D output flag, which overrides the display flag.

    • Bring in an external COP.

      1. Turn on Use External COP.

      2. Set COP Path to the path of a COP node that’s outside of the SOP network.

    You can now wire the COP Network SOP into other SOP nodes in the network.

Note

Some SOP nodes let you point to a COP network. SOPs that supported this for COP Network - Old now support this for the new COP Network.

Bringing COPs into LOPs for materials

You can create a Quick Surface Material LOP in your Solaris network to bring a COP network into your LOP network for use in MaterialX. See Quick Materials for how to use this LOP.

You can also use a Scene Import LOP to bring a SOP with a COP Preview Material into your LOP network.

As an alternative, you can follow these steps to bring COPs into LOPs using a Karma Material Builder subnetwork.

  1. Create a Material Library LOP in your Solaris network.

  2. Dive into the Material Library LOP.

  3. Add and dive into the Karma Material Builder subnetwork node.

  4. Add a MtlX Tiled Image VOP.

  5. Set File to the path of a node in a COP network. You must prefix the node’s path with op:. For more more information about the op: prefix, see Use data from a node instead of a file (op:).

    You can now use the COP node’s pattern and data in your MaterialX workflow.

Using COPs as materials

Follow these steps to apply COP outputs as materials on SOP (geometry) nodes.

  1. Create a COP Preview Material SOP in your SOP network.

    Tip

    In the Copernicus network, you can instead use the Preview Material COP and wire your nodes into the different inputs to test how the materials display.

  2. Wire the SOP on which you want to add materials into the COP Preview Material SOP.

  3. Go to Material ▸ Base in the COP Preview Material SOP.

  4. Under Base Color, set Source to COP.

  5. Set Base Color COP to the path of a node in a COP network.

  6. (Optional) To render your geometry with the materials applied, go to /stage and add a Scene Import (All) LOP. This brings in your geometry so you can render it using Karma.

Using SOPs from COPs

Follow these steps to alter geometry wires with SOPs. The SOP Invoke COP streamlines the processing of geometry in a COP network.

  1. Create geometry in your COP network. For example, add a SOP Geometry COP and dive into the node to create geometry.

  2. Add a SOP Invoke COP.

  3. Wire the geometry into the SOP Invoke COP’s input#.

  4. Dive into the SOP Invoke COP.

  5. Add and configure SOP nodes between the Block Begin Compile and Block End Compile SOPs. These nodes run on the input geometry. The node parameters in the invoked block are evaluated in their original locations.

    Note

    Only compileable SOPs can be used in this block.

  6. Go back up to the COP network. The SOP Invoke COP output# contains the altered geometry, which you can wire directly into a COP node.

Note

The SOP Invoke COP takes geometry wires to run SOPs onto, while the SOP Import and SOP Geometry COPs read a SOP network from which they create a geometry wire.

Starting a live render

See Live rendering in Solaris for information about how to start and stop a live render session.

Copernicus

Basics

Next steps

  • Slap comp

    Slap composite (slap comp) is a fast image manipulation you can use to view approximate and live results of a final composite.

  • OpenFX

    Describes what OpenFX is and how to use it in your network.

  • Hatching

    Describes how to use hatching in your Copernicus network.

  • VDBs

  • How to use ONNX Inference

    Describes how to apply inference using a model in the ONNX Inference node.

  • Filter List

    The Filter List window lets you quickly apply effects in your scene.

  • Copernicus tips

    Useful tips and information while using COPs.

Dynamics

Advanced concepts

  • Normals

    Defines the normals that the Copernicus network uses.

  • Spaces

    Defines the spaces that the Copernicus network uses.