The paper presents an improved illumination model for shaded computer graphics, which aims to enhance the realism of rendered images by incorporating global illumination information. The model uses a tree of "rays" extending from the viewer to surfaces and light sources to calculate the intensity of light received by the viewer. This approach allows for accurate simulation of true reflection, shadows, and refraction, as well as anti-aliasing. The model is implemented using a visible surface algorithm that traces rays from the viewer to the scene, creating a tree of intersections. The algorithm also includes techniques for handling curved and polygonal surfaces, and it supports anti-aliasing by low-pass filtering regions of abrupt intensity changes. The results show that the model generates very realistic effects, though it has room for improvement in handling diffuse reflection from distributed light sources and specular reflections from less glossy surfaces. The implementation is slow but shows potential for future optimization, particularly in multiprocessor systems.The paper presents an improved illumination model for shaded computer graphics, which aims to enhance the realism of rendered images by incorporating global illumination information. The model uses a tree of "rays" extending from the viewer to surfaces and light sources to calculate the intensity of light received by the viewer. This approach allows for accurate simulation of true reflection, shadows, and refraction, as well as anti-aliasing. The model is implemented using a visible surface algorithm that traces rays from the viewer to the scene, creating a tree of intersections. The algorithm also includes techniques for handling curved and polygonal surfaces, and it supports anti-aliasing by low-pass filtering regions of abrupt intensity changes. The results show that the model generates very realistic effects, though it has room for improvement in handling diffuse reflection from distributed light sources and specular reflections from less glossy surfaces. The implementation is slow but shows potential for future optimization, particularly in multiprocessor systems.