This is a rescaled dome structure. It was 18mm but by scaling it up by 166.6% it's now scaled for 28mm miniatures.
There are two versions available - one with doorways and one without, which is the one I printed. I liked the level of detail and have since remixed it myself to include some of the Warhammer 40K icons/symbols.
This was done in PLA on the Cetus at 0.2mm using a 13% infill.
A saltbeard Grognard who's glad he never grew up enough to lose his imagination.