TECHNICAL PAPER Building Tools for Houdini 9

3.Anatomy of a ToolPython ScriptAll tools must have a Python script that defines an action such as placing a node or changing parameters onan existing node. Houdini provides a large number of Python modules in $HFS/scripts/python which will beexamined in more detail later.There are two places to define a tool interactively. The first is a Shelf Dialog, the second is as a part of anDigital Asset Op Type Properties Dialog. The dialogs themselves are almost identical, so let’s look at theShelf for an example.Shelf Edit Tool DialogChoose a Shelf Tool to examine – say “Box” from the Create Shelf.RMB on the tool icon and “Edit Tool…” to see the following dialog:The tool must have▪▪▪▪▪▪▪▪Figure 7 - Fig. 7 – Edit Tool DialogA location on Disk (Save To)A nameA labelA script (or it will do nothing and not show up in the interface)All other settings are optional, but important for good tool behavior. Let’s look at them one-by-one.Options:▪ ▪ Save To location is the name of the shelf file containing the tool.. All shelf files should be savedwithin the $HOUDINI_PATH in a toolbar folder or somewhere in the $HOUDINI_TOOLBAR_PATHif it is defined. All shelf files have to have a .shelf extension. Shelves that are not part of the Houdinidistribution will typically be saved in $HOME/houdini9.0/toolbar8 | TECHNICAL PAPER Rev 1.0