1. An image processing method executed in an apparatus for transforming coordinates of shape specific points that specify a shape of a graphic representing an object so as to generate graphics data representing a behavior of said object, said method comprising the steps of: setting a transformation matrix having elements each of which is expressed by a function having a time as a variable, said function converging to a corresponding element of a matrix that represents a behavior of said object when said object is assumed to be a rigid body; and transforming the coordinates of said shape specific points using said transformation matrix and generating said graphics data based on the coordinates obtained.