The version of Fusion that went out this past weekend has a lot of new features but for the API the most important is the introduction of add-in support. Previously there was only support for scripts. There’s not a big difference between a script and an add-in but that small difference makes a huge difference in how it’s seen and used by the user.
A script is run by the user by executing the “Scripts and Add-Ins” command from the File menu, choosing the script they want to run, and clicking the “Run” button.
An add-in has the option to be loaded automatically when Fusion starts. Taking advantage of this small difference, an add-in can use the API to create commands and add them to the Fusion user-interface. The add-in’s commands appear to the user like any other Fusion command. Unless explicitly unloaded by the user, the add-in remains running in the background throughout the Fusion session so it can respond whenever any of its commands are run and do whatever that command is supposed to do.
The dialog below shows the new dialog for creating a new add-in or script.
For this release there are four new topics in the Fusion API help that discuss add-ins and some related technology, that although isn’t exclusive to add-ins is more important for a typical add-in workflow. These new topics are shown in the picture below.
Add-ins also make it easier to give your program to someone else, either by giving them the add-in files or package it into an installer. The files can simply be copied to the correct location on the users machine and Fusion will automatically find the add-in and load it the next time is starts. An installer does the same thing but simplifies the copy process. The next time Fusion is started, the new commands added by the add-in are immediately available to the user.