While modelling the floor as a diaphram(by selecting all the points in the floor plan and assigning a diaphram for them) I concentrate all the floor mass to a single point i.e the center of gravity of the floor plan and use assign joint masses option to put all the mass and mass moment of inertia to that single point.However As I  work in Kn.m units in what units I have to assign those masses?In kN or in tons or in kg?I mean how sap 2000 recognizes the mass?As a vector or as a scalar quantity?