Node and parameter paths

Every node and parameter has a unique pathname you can use to refer to it.

The organization of data in Houdini is very similar to a UNIX file system.

The root path is /.
The next level is the list type. This is one of obj (objects), comp (compositing operators), out (render output operators), part (particle operators), ch (channel operators), shop (shader operators), or vex (VEX builder operators).
Next comes any subnet names.
Next is the node name.
You can also specify a parameter name inside the node.

As in a filesystem, you can use . (here) and .. (up one level) to refer to nodes and parameters by their position relative to the current context. For example, in a sphere node at /obj/geo1/sphere1, you can refer to the radiusy parameter on another sphere node at the same level with ../sphere2/radiusy.

Examples ¶

/obj/geo1/sphere1/tx

The Translate X parameter of sphere1 inside geo1.

/comp/comp1/color3/colorr

The red color component of the color3 color COP inside COP network comp1.

Networks and parameters

Networks ¶

Network editor

How to create, move, copy, and edit nodes.
Network navigation

How to move around the networks and move between networks.
Connecting (wiring) nodes

How to connect nodes to each other to make them work together.
Network types and node flags

Flags represent some state information on the node, such as which node represents the output of the network. Different network types have different flags.
Badges

Badges indicate some status information about a node. They usually appear as a row of icons below the name of the node.
Node Info

The node info window shows a quick overview of statistics and information about a particular node.
Find nodes in a network

How to use the Find dialog to find nodes based on various criteria.

Editing parameters ¶

Parameter editor

How to change the behavior of nodes by changing their parameters.
Ramp parameters

Explains the tricks to working with ramp parameters.
Pattern matching in parameters

An explanation of the special characters available in pattern-matching parameters.
Modifying a node’s interface

How to change the parameter interface of a node.
Parameter references

How to create references between parameters and create node copies that reference the original.

Next steps ¶

Laying out nodes

How to automatically clean up, align, and distribute nodes.
Organizing, customizing, and annotating nodes and networks

How to keep your networks neat and well documented.
Node and parameter paths

Every node and parameter has a unique pathname you can use to refer to it.
Visualizing dependencies

How to display lines and indicators representing channels references between nodes.
Network editor options

Guide to network editor options.
Network editor shortcuts

A quick reference for hotkeys and user interface shortcuts in the network editor.

Rename nodes

Expressions ¶

Parameter expressions

You can enter expressions into a parameter so its value is computed instead of being static or keyframe animated.
Expressions in filenames

How to use variables and expressions in file path fields to generate numbered and unique filenames.
Spare parameters

How to add extra parameters to an individual node.
Expression cookbook

Tips and tricks for writing expressions to accomplish various effects.
List of expression functions

Expression functions let you compute the value of parameters.

Guru level ¶

Recipes: saving and recreating node and parameter presets

How to save parameter settings and groups of nodes so you can recreate them when needed.
Parameter Motion Effects

Motion Effects let you easily add secondary motion to keyframed parameters (usually translate, rotate, or scale parameters), such as jitter or overshoot.
Custom HScript expression functions

How to add custom functions to the HScript expression language.

Reference ¶

Network editor menus

Explains all the menu items in the network editor menus.
Parameter editor