Connecting (wiring) nodes

How to connect nodes to each other to make them work together.

On this page

Overview
How to
Wiring tips
Routing with dots
- Pinning dots
Reordering inputs
Actions

Overview ¶

In Houdini networks, nodes have input and output connectors, which you connect together with wires.

Wires have different meanings in different network types:

In Object (OBJ) networks, the connections control parenting (connect child objects to the outputs of parent objects).
In geometry (SOPs), compositing (COPs), dynamics (DOPs), and VOP networks connections control the flow of data through the network.
In render output (ROPs) networks, connections control dependencies between render passes (connect later renders to the outputs of prerequisite renders).

How to ¶

To...	Do this
Connect node inputs and outputs	Click one node’s output and then click another node’s input (or vice-versa) to wire them together. or Drag from one connector to another instead of using separate clicks. (You can click in empty space to cancel the wiring operation.)
Create a new node attached to an existing input/output	To branch a new wire off an input or output connector, click the connector to start a wire, then press `⇥ Tab` and use the menu to choose which type of node to create and press `Enter`. To insert a new node just before a connected input, or just after an output, -click the connector and use the menu to choose the type of node to insert. You can press `⇥ Tab`, choose the node type, and then while placing the node, you can drag from a connector to wire the node and place it at the same time. You can press `⇥ Tab`, choose the node type, and then press `⇧ Shift` + `Enter` to automatically wire the new node into the output of the “current” node (the node shown in the parameter editor, usually the most-recently selected node).
Insert a node into an existing wire	Drop a node onto an existing wire to insert it between the wire’s input and output.
Disconnect wires	There are several ways to disconnect a wire. Shake a node to disconnect its inputs and outputs. Select a wire and press `⌦ Del` to delete it. Click the connection’s input, then click in empty space. Right-click the wire and choose Disconnect.
Branch an already-connected output to another input	Click an output that is already connected to something. Click the additional input.
Wire nodes together by drawing across them	Hold `J` and drag across two or more nodes to wire them together. For nodes with just one input and output, you can draw anywhere over the nodes. For nodes with multiple inputs or outputs, try to draw over the connector you want to wire up. The tool remembers the initial drawing direction, so you can zig-zag to hit nodes not in a direct line.
Cut wires by drawing a line	Hold `Y` and drag a line across a wire or multiple wires to disconnect them.
Cut wires	Hold this key and drag to cut any wires you drag over.

Wiring tips ¶

Right-click a wire to see a menu of operations you can perform on the wire.
You can hold Space and pan and zoom the network view while connecting, if you need to bring the node you're connecting to into view.
Press Alt + on a node to get a menu of connectors to start wiring. This can be useful when you're zoomed out so far it’s hard to click the connectors.
If you select multiple nodes and connect one of their outputs to a multi-input, Houdini automatically connects the outputs of all the selected nodes. This is useful when you want to connect a bunch of nodes to a Merge node.
You can hover on an input to get a tooltip explaining the purpose of the input (if the node author wrote help for the input).

Routing with dots ¶

The network editor lets you add “dots” to wires to route them away from a straight path between the output and input.

To...	Do this
Add a dot to an existing wire	Hold `Alt` and click the wire.
Add a dot while creating a new wire	Click the output/input connector to start the wire, then `Alt-click` one or more times to add dots, then click the destination connector to finish the wire.
Rewire from a dot	Hover the mouse pointer over the dot to show input and output connectors. You can wire to/from these connectors like the usual connectors on a node.
Gather multiple wires into a dot	If you hold Alt while dragging a dot, it will “pick up” wires it crosses like walking through spiderwebs. This is a quick way of gathering a bunch of wires together.

Pinning dots ¶

Dots have two states: pinned and unpinned. Alt-click a dot to toggle this state. A pinned dot has a life of its own. You can disconnect all the wires into and out of it, and it sticks around. A pinned dot is very much like a dot in Nuke, and lets you build chunks of networks, with dangling dots as scaffolding which you can connect to later.

An unpinned dot is meant to allow for simple wire routing without a lot of overhead. An unpinned dot gets automatically deleted if all the wires into or all the wires out of it get deleted (since without a wire passing all the way through it, an unpinned dot serves no purpose).

Reordering inputs ¶

Some nodes, for example the Merge geometry node, have “multi-inputs” that let you wire in multiple inputs.
In some nodes with multi-inputs, the order of the inputs is sometimes significant. For example, Render nodes (ROPs) render their inputs in order.

To...	Do this
Change the order of inputs	Select the node in the network editor. In the parameter editor, scroll down to the bottom of the panel. For nodes with multiple inputs there will be a list of inputs. Drag and drop the inputs in the list or click the up-arrow icons to reorder them.
Quickly rotate input order	Select the node. In the network editor, choose Edit ▸ Rotate input connections or press `⇧ Shift` + `R`.

Connecting (wiring) nodes

Overview ¶

How to ¶

Wiring tips ¶

Routing with dots ¶

Pinning dots ¶

Reordering inputs ¶

Actions ¶

Networks and parameters

Networks ¶

Editing parameters ¶

Next steps ¶

Expressions ¶

Guru level ¶

Reference ¶