To do this, software programs generally use one of three methods. The first is the same as the manual method described earlier that makes use of the room position multiplier table. The second is the Descritization Method in which the room is broken up into smaller sections. The calculations of light flux hitting and leaving each small section are calculated and then summed up to find the contribution to the point. This means that the designer can review exitance and illuminance patterns on surfaces.
Some programs can account for obstructions in a space.
The third method is the Radiant Flux Transfer Method in which the program calculates the percentage of light reflecting from surface to surface. Radiant transfer factors and configuration factors are used to describe how light reflects off of surfaces and how that reflection contributes to the point. The program output usually includes an Iso-footcandle plot for the room and the average illumination found by taking the average of all the points calculated. Some programs may also include the lighting power density for the room in watts per square foot and the room surface luminance in candelas per square foot. Sophisticated and more expensive software might include daylighting analysis capability, partition analysis, Computer Aided Design interfacing, on-screen visual renditions of the room to show the effect of the prescribed lighting system and quality metrics.