Considering that 3D enhancement rendering algorithms has not involved shadow so far, a new algorithm on enhancing models with approximate soft shadow is proposed. A new scaling method is designed for simple illumination scene, and lighting value of each pixel is modified using this method, so that details on surfaces are more prominent. Then the approximate soft shadow is introduced in that silhouette edges are extracted using the GPUs geometry shader and then extended to generate penumbra area. The radiance intensity and shape of the penumbra area is altered by adjusting the attenuation parameter, making the approximate soft shadow darker and smaller. The method is validated to be efficient as the whole scene is enhanced consistently.
