Nailed it. I started iOS development using Obj-C++ but switched to C# after a couple years because of my familiarity and comfort in that ecosystem. At this point I've used it for 10 years on several iOS and Mac apps and know its ins and outs. I've been accused of making my own job harder but honestly it feels the opposite for me. The .NET debugger, reflection, choice of languages, package ecosystem, it's all very lovely.

I’m a little surprised he went with SceneKit for rendering. I don’t expect it to go away anytime soon, but it also hasn’t received a lot of love from Apple in the past several years.

Edit: of course it can be great to use what you are comfortable with. Done (and really, really good, is better than perfect.

The way he is using property definitions with SetUndoableProperty seems like a really good fit for Swift’s property wrappers. Instead of writing getter and setters for every property you could just write them in once in the property wrapper definition and then annotate each property with @Undoable.

There’s obviously something wrong with that, because now he is unable to release his app on other platforms where it would probably find a larger audience.

To be clear, C# is a great language for this project. It’s the choice of using a platform specific library (SceneKit) that baffles me.