Illustrator and macOS have been around for many years, so system compatibility can get confusing; however, this list and an open-source shell script will fix you right up.
Xcode 9 or above is required to develop Illustrator plug-ins for macOS using CORE. We have tested full compatibility up to Xcode 13.4.1.
To be able to compile against all versions of CORE, your Xcode binary will need to be modified for legacy support. We recommend downloading Xcode 13.4.1 or 12.4.0, 11.7.0, 10.3.0, and 9.4.1. Otherwise, you will only be able to compile against the version of CORE corresponding to the macOS SDK versions listed above.
All the Xcode modifications are straightforward and are fully automated by this XcodeLegacy script on github. Simply download it (or checkout its git repository) and follow the instructions - you can specify certain options when running the XcodeLegacy command to only add macOS 10.13 through 10.15 to Xcode 12 or 13, if you'd rather not download Xcode versions below 9.4.1 as well.
It is worth noting that only the older macOS SDKs are required to develop for older versions of Illustrator (not e.g. the older compilers or linkers); if you'd like to manually modify Xcode 12 or 13 to compile for all versions of Illustrator, simply extract the MacOSX10.x.sdk folder from each older version of Xcode and copy it into the Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs folder of Xcode 12 or 13, and modify the associated Info.plist file there to remove the "MinimumSDKVersion" entry.
Microsoft Visual Studio 2015 Professional or above is required to develop Illustrator plug-ins for Windows using CORE.
Hot Door uses Microsoft Visual Studio 2015 Professional and has not tested later versions.
No modifications or additional downloads are needed to develop plug-ins for CC 2019 through 2023 (23-27).
CORE contains four sample plug-ins: Annotate, Panel, Skeleton, and Tool.
The Annotate sample implements a simple rectangle drawing tool, which annotates its geometry during dragging.
The Skeleton sample simply acts as an empty plugin that performs no function, but which Illustrator recognizes and loads successfully. This is to provide a good foundation on which to start building your own plugin (see below).
The Tool plug-in implements a gear drawing tool. This demonstrates the creation of tools, modal dialogs with UI elements, preferences, and Illustrator art drawing.
The Panel plug-in demonstrates the creation of panels with UI elements, notifiers, timers, and Illustrator art object iteration.
The easiest way to get your plug-in started using CORE is to duplicate and modify the Skeleton plug-in as a starting point.
You have two choices at this point: either start working with Skeleton as-is and add your own code, or follow these instructions to eliminate all traces of "Skeleton" and "skel" from your project.