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The Houdini Object Model (HOM) is an application programming interface (API) that lets you get information from and control Houdini using the Python scripting language. HOM replaces the functionality of Houdini’s previous scripting solutions, the expression language and HScript.
In Python, the hou package is the top of a hierarchy of modules, functions,
and classes that define the HOM. The
hou module is automatically imported
when you are writing expressions in the parameter editor
and in the
hython command-line shell.
On Mac OS X, Houdini uses the system’s Python.
On Windows, Houdini uses the version of Python installed with Houdini.
On Linux, Houdini does not look at
$PATH when trying to search and load the Python library. Instead it searches all the paths in
/lib, and then
/usr/lib. If it can’t find a suitable Python library in the system, it uses the one in
$HFS. If your Python library is not in a standard location, you should add its directory path to
You can write parameter expressions in Python instead of the default Hscript expression language.
Various places in Houdini where you can customize behavior using Python scripting.
How to write Python scripts for shelf tools.
These examples demonstrate simple uses of the Houdini’s Python scripting API.
You can use HOM to store and retrieve arbitrary data on individual nodes.