This paper presents an improved illumination model for shaded display, which uses global information to calculate intensities and supports a ray tracing visible surface algorithm. The model accounts for both specular and diffuse reflections, as well as refraction and transmission through transparent objects. It introduces a new shading model that combines diffuse and specular components with transmission, allowing for more accurate simulation of light behavior. The model also incorporates anti-aliasing and handles the visibility of surfaces through recursive ray tracing. The improved model extends traditional visible surface algorithms by incorporating global illumination information, which is essential for accurate rendering of complex scenes. It uses a recursive approach to trace rays from the viewer to surfaces and light sources, allowing for the simulation of multiple reflections and refractions. The model also includes a technique for simulating surface roughness by adding random perturbations to surface normals, which helps in generating realistic specular reflections. The visible surface algorithm uses bounding volumes to efficiently determine which objects are visible and to eliminate unnecessary processing. It also includes mechanisms for anti-aliasing, which is achieved by low-pass filtering the image before sampling. The algorithm is tested on various scenes, demonstrating its ability to produce realistic images with shadows, reflections, and refractions. The results show that the algorithm is effective in generating high-quality images, although it is computationally intensive. The algorithm's performance is optimized by using efficient intersection processing and a division of tasks between processors in a multiprocessor system. The paper concludes that while the model has significant potential, there is still room for improvement, particularly in handling diffuse reflections from distributed light sources and specular reflections from less glossy surfaces.This paper presents an improved illumination model for shaded display, which uses global information to calculate intensities and supports a ray tracing visible surface algorithm. The model accounts for both specular and diffuse reflections, as well as refraction and transmission through transparent objects. It introduces a new shading model that combines diffuse and specular components with transmission, allowing for more accurate simulation of light behavior. The model also incorporates anti-aliasing and handles the visibility of surfaces through recursive ray tracing. The improved model extends traditional visible surface algorithms by incorporating global illumination information, which is essential for accurate rendering of complex scenes. It uses a recursive approach to trace rays from the viewer to surfaces and light sources, allowing for the simulation of multiple reflections and refractions. The model also includes a technique for simulating surface roughness by adding random perturbations to surface normals, which helps in generating realistic specular reflections. The visible surface algorithm uses bounding volumes to efficiently determine which objects are visible and to eliminate unnecessary processing. It also includes mechanisms for anti-aliasing, which is achieved by low-pass filtering the image before sampling. The algorithm is tested on various scenes, demonstrating its ability to produce realistic images with shadows, reflections, and refractions. The results show that the algorithm is effective in generating high-quality images, although it is computationally intensive. The algorithm's performance is optimized by using efficient intersection processing and a division of tasks between processors in a multiprocessor system. The paper concludes that while the model has significant potential, there is still room for improvement, particularly in handling diffuse reflections from distributed light sources and specular reflections from less glossy surfaces.