The present invention is related to rendering computer animated video and/or images generally, and to improving the calculation of diffusely reflected light. The present invention includes a system and method of computing diffusely reflected light at one or more positions on surfaces in an object scene from object scene data. The present invention typically includes the step of and/or instructions for selecting a non-regular order for processing a plurality of positions on a surface—the plurality of positions having been predetermined. The present invention also includes the step of and/or instruction for processing the plurality of positions in the non-regular order. This processing typically includes computing diffusely reflected light at a position in the plurality of positions by reference to diffusely reflected light incident on the position when deriving the diffusely reflected light at the position by reference to diffusely reflected light at other positions computed by reference to diffusely reflected light incident on the other positions is inaccurate. Alternatively, deriving the diffusely reflected light at the position by reference to the diffusely reflected light at the other positions computed by reference to diffusely reflected light incident on the other positions when deriving the diffusely reflected light at the position by reference to the diffusely reflected light at the other positions is accurate.