This plaster model was just removed from the 3D-printed shell behind. It dropped out easily (after tapping it at-an-angle on the corners), this worked well despite the resolution lines on the surface. While I could have spent time sanding and smoothing the inside of the shell-mold, it is actually far easier to smooth the surface of the plaster form after extraction. Seconds with a metal rib completely smooths any of the surfaces. And remember, it is easier to remove plaster items cast inside of 3D-printed molds rather than cast around the outside of them.
Standard 3D printing technology (not printing with clay itself) is very useful to potters and ceramic industry in making objects that assist and enable production.