Well, I’ve been looking at Blender 3.0 Beta to see what might be new. And it seems that “Geometry Nodes” have had a serious updating. They were introduced in Blender 2.92 and the latest version has brought some dramatic changes. I gather they were introduced to replace the Particle System functionality which I used to scatter rocks and trees around landscapes. But things have changed - now they are being used to create buildings :
I downloaded Blender 3.0 Beta yesterday and installed @JCPalmer 's .babylon exporter. Everything went well.
I will add some comments later today.
Stay Safe All, gryff