1. A method for generating images to be viewable on a display using a computer that are generated based on scene geometry obtained from computer-readable storage and animation data representing changes over time of elements of the scene geometry, the method comprising: receiving at least some of the scene geometry and at least some of the animation data; receiving motion depiction parameters; generating motion fragments representing elements of the scene geometry over a nonzero time period; generating shading for the motion fragments, wherein the images including contributions from the motion fragments would suggest motion of the represented elements to a viewer of the generated images; and combining the shading for the motion fragments with shading for the scene geometry at an instant in frame time equal to a current frame time.