Actually this geometry could be 3D printed. Here is an image of the original 3DM file (gray) and the GH geometry (green) made by Setting and Internalizing the 3DM geometry:
The 3DM geometry has 3D thickness, so it could be printed OK. But the floors are missing - I’m not sure why. Nevertheless, adding the floors to the GH geometry would be easy - just get the outside edges and extrude them down by a value of the desired thickness.
The central slanting floor is a problem because it isn’t attached to anything. Barring the use of some sort of levitation device it should be a simple task to add some supporting structure - like the legs supporting the table-like surfaces on the outside perimeter.