after i read this:
why not if possible integrating Blenders Cycles render engine in Unreal Engine4!!??? Well Cycles is Real Time Now.. Cool I guess ;) - YouTube has Octane Render Engine!
OTOY's Jules Urbach on OctaneRender + Unity Integration - Unite 2016 Keynote - YouTube
or aditional Physics Library Like Bullet Physics or Chronos:
http://bulletphysics.org/wordpress/
https://projectchrono.org/