Cool thread.
Sassanid architecture is something I really have not familiarize myself with, even though their empire was one that caught my interest; besides Persian culture in general being of interest, the fact that they (as well as their predecessors, the Parthians) were the rival to Rome.
Of course Achaemenid architecture is easy to conjure up with visions of Persepolis, as is the post-Mongol stuff (notably the Safavids).
But even seeing pictures of Ctesiphon, it's hard for me to picture what their buildings looked like. Possibly with seeing more, a clearer image can surface.