I had another thought, though I haven't attempted it yet, but it really leaves you with just one angle of approach, a vector export would give you sides, which than you could use as masks in PS etc. You could than "retain" the rock/object on a side, and then all others blur it out, and adjust intensity and would assentialy create soft buildup around the object leaving one side intact. You'd have to use the "one side" mask to mask the Y data and blur out the rest I'd imagine.