Distribution ray tracing uses Monte Carlo integration to solve the rendering equation. This technique was introduced by Cook et. al, and was notable because of its simplicity and its ability to simulate areal luminaires, camera lens e ects, motion blur, and imperfect specular re ection[5]. Distribution ray tracing has been extended and modi ed by many researchers, most no- tably by Kajiya who added true indirect illumination[12]. Distribution ray tracing has also been used as the viewing component of radiosity systems (e.g [37, 3]). In this paper we examine some of the central issues of distribu- tion ray tracing that have been overlooked in the literature but are still of importance and modi ed by many researchers, most no- tably by Kajiya who added true indirect illumination[12]. Distribution ray tracing has also been used as the viewing component of radiosity systems (e.g [37, 3]). In this paper we examine some of the central issues of distribu- tion ray tracing that have been overlooked in the literature but are still of importance