In an animation processing system, 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 scene geometry elements, but also images can be modified to include shading that is a function of positions of objects at other than the current instantaneous time for a frame render such that the motion effect shading would suggest motion of at least one of the elements to a viewer of the generated images. Motion effects provide, based on depiction parameters and/or artist inputs, shading that varies for at least some received animation data, received motion depiction parameters, for at least one pixel, a pixel color is rendered based on motion effect program output and at least some received scene geometry, such that the output contributes to features that would suggest the motion.