Copy a lot of different content from on project to another

[Deeeds]

How can I treat one project as a development experiment zone for a more final project, and easily copy lots of things over from the experiment zone to the actual project whenever I'm happy?

Kind of like how Playgrounds is to Xcode projects...

[Murtaza]

You can't do that. Each project is "sandboxed" into it's own environment.

What you can do is create a scene within your project as a playground, then copy objects to another scene when needed.