yes you should be able to generate a seamless mesh. youve gone very high, with this now, when i said about adding the groves between the bricks i meant in ZB, i reakon you could getthe same shape (minus corner sillohette) with a better rounder arch for half the tris.
thats Zbrushed? id say you need to go back and give it another go if it is. firstly if your going to spend that many polys on pulling the stone out then that arch is woefully low polys add two extra spans at least. secondly- get rid of all those 90 degree angles pull the exterior surface in to do this you will then be able…