Like your idea - and realize it's a WIP - but the lava as it looks in this render doesn't work to me, but i can't see the final work as you do.... Just off top of head - where everything is so precise, neat and clean.... how about just having a jaggedy crack starting across the center of the table forming the divide.... Only other idea that comes to me at the moment is having the end chairs - instead of facing, having each cantered a bit towards opposite directions (i.e. top chair angled more to the viewer's viewpoint - and the bottom chair angled with it's back to us..... Don't feel to comfortable really giving you any sort of suggestions on this - cause i like your idea - and look forward to seeing the completed scene. Nice one. best, hewsan