I thought maybe the ability to use 3D in javafx might obviate the need to have a separate P3D window that you mentioned in your first post.
If you feel like experimenting, try running the code without the separate ‘code’ folder. I can’t tell if you are able to run the demo because you successfully re-compiled Processing4 or whether it is because you added the jar files to a ‘code’ folder. Whatever you did obviously worked, but it would be nice to know which of the two methods is responsible for your success. Thanks again.