This read-only variable will return the x position of the instance's center of mass. This is calculated automatically based on the density, inertia and mass of the instance as defined by the appropriate functions
phy_com_x;
Real (single precision floating point value, or undefined if the instance is not physics enabled)
xx = phy_com_x;
yy = phy_com_y;
The above code sets two variables to the x and y position of the instances center of mass.