Load and manage assets on disk

Operator type libraries (OTLs)

You save digital assets in operator type library files (OTLs). Depending on where you save the OTL file, you can make it available to every user, to every project, to all files in one project, or just in one scene. An OTL can exist as a file on disk or be embedded in a scene file.

Tip

If you want to disable saving of an embedded OTLs, turn off Save operator definitions to Hip file in the configuration section of the operator type manager . You can also choose whether to receive a warning when you open a scene file with an embedded OTL and more recent definitions are available on disk.

You can use OTLs to share digital assets between scene files without copying and pasting, and to limit access to the internals of a character.

The operator type manager (Windows> Operator Type Manager) lets you manage operator type libraries.

Making OTLs available to Houdini

Houdini searches for OTLs in the directories specified by the $HOUDINI_OTLSCAN_PATH environment variable. The default path is @/otls, where @ means the standard Houdini path ($HOUDINI_PATH), so by default Houdini looks for OTL files inside any otls folders in the directories listed on the Houdini path. This is similar to how Houdini searches for other types of files, such as scripts in folders named scripts inside the directories on the Houdini path.

Older versions of Houdini used a different method of locating OTL files, where the filenames of OTL files were listed in files named OPlibraries, and Houdini looked for the OPlibraries files in directories specified by the $HOUDINI_OTL_PATH variable. The new method is simpler and more consistent with the rest of Houdini. However, to re-enable the OPlibraries method, choose Windows > Operator Type Manager, click Configuration, then turn on Use OPlibraries files to find OTLs.

How to load digital assets

To...	Do this
Install the assets in an operator type library (OTL) file	Choose File > Install Digital Asset Library. Select the digital asset file you want to install. Use the Install Library To option to choose where you want the type library to be available.
Uninstall an operator type library	Choose Windows> Operator Type Manager to open the operator type manager window. Press on the OTL name and choose Uninstall.
Load and unload asset libraries through HScript	To install/uninstall operator types without using the interface (for example, to install a large number of types, or install types on a headless server), use the optyperead, optypewrite, and optypeuninstall HScript commands.

Tip	To control which version is used when multiple versions of an operator definition are available, use the options on the Configuration tab of the operator type manager window .

Manage digital assets and asset versions

To...	Do this
Open the operator type manager	Choose Windows> Operator Type Manager to open the operator type manager window .
Find out which `.otl` file has the definition of an asset	Press on the node tile of an instance of the asset.
Copy an asset from one library to another	Choose Windows> Operator Type Manager to open the operator type manager window. In the tree, open the Operator Type Libraries item and navigate to the library and asset you want to copy. Press on the asset and choose Copy. Set Operator name to the internal name the asset will have in the new library (see naming digital assets). Set Save to library to the library (`.otl`) file to copy the asset into. To install the library immediately, choose a location from the Install library to menu.
Manage multiple available versions of an asset	In the operator type manager, press on an asset and choose Jump to current definition to highlight the library providing the current definition of an asset type. To move between different definitions of an asset, press on an asset and choose Jump to next definition. To choose a different version as the current definition for the asset, press on the asset and choose Use this definition.
Display information about an operator	Press on the operator name.
Embed files in an OTL	See edit the contents of an OTL .
Copy an operator from one Operator Type Library to another	Press on the operator you want to copy and choose Copy.
Remove an operator from an OTL	Press on the operator you want to copy and choose Delete. You can’t delete an operator that is in use.