Hello!  
	i'm working on my personal project, i trying recreate "ice hummocks" which move through objects and collide.  
	Based on this wiki page i recreate basic formula    where p = 1000, g = 9.8, V (volume of the pieces)
 
	But problem is that i working with packed objects and don't know "area of the party of an object.". and pieces start spinning after a while.  
	(i think it could be solved through dot product, but i stuck)
 
	scene file!!     https://drive.google.com/open?id=0B6Rw9sQd7tjLTHNfYTNTRE1NMFE
 
	  
	reference