i created an assembly in solidworks, it consists of 3 parts. the mainframe, and an arm on each side. One of the arms is a mirror image of the other. When i run Cosmos, and use the gravity feature, it recognizes that only '1' of the arm has mass so the C.G. arrow is offset from the middle. i 'defined' material for all, and in the tree it even lists the mirrorARM to have a material of ASTM36 steel. Has anybody had this problem??