Building plugins on a Mac
Xcode
The development system for macOS is called Xcode, and like Visual Studio on Windows, there are multiple versions. Which one you have depends on the version of macOS in your machine but in general, the later versions of macOS allow you to install different versions of Xcode on your machine. The MAXON developers page will show you which version to use, but again, you can use a later version if required. Note that not all versions of Xcode will install on all versions of macOS, you may find that an Xcode version which is too early or too late for your version of macOS won't install, or will install but won't run.
One very important point is that if you want to build a version of your plugin to run on the Apple M1 CPU, you will need Xcode 12 - earlier versions don't have the dual-binary capability so the compiled plugin will only run on an Intel Mac. Note that Xcode 11 requires at least macOS version 10.15 (Catalina) and the latest versions of Xcode 12 require macOS 11 (BigSur).
Yes, it's complicated which is why I prefer to develop on a PC and build on a Mac only when absolutely necessary. This Wikipedia page sums up the requirements nicely. It is, however, relatively simple to dual-boot a Mac with multiple versions of macOS which makes life a little easier. In addition, there is no point worrying about this if you are only building for C4D versions earlier than R23, as that version is required to run on the M1 chip - earlier C4D versions won't do so, so there's no need to build an M1 version of your plugin in that case.
Of course, to test that the plugin works on both Intel and M1 machines, you will need two machines so many small developers are likely to build on one flavour of machine and assume (hope?) it also works on the other one.
Fortunately, once you have an appropriate version of Xcode installed, you can build the plugin and it should just work.
Page last updated June 23rd 2021