...sunken rooms

Not entirely sure how such a function could be easier than just creating a level. If you think about negative elevation for objects, this has been proposed but I had the impression that Puybaret has yet to be convinced ...

... steps are curved, ...option to define curves for room boundaries.

Curved steps / stairs can be defined in the Furniture Library Editor so they cut the floor (and ceiling) perfectly. This guide tries to explain how.

...it's an absolute delight! [;)]

What impresses me the most after 9 months of amateur use, is how every constructional challenge finds a solution in SH3d (or at the very least a workaround) - usually described somewhere in the FAQ or the forum. And given the ease of use, that is quite remarkable.

ok