Modern Rapid Prototyping (RP) technology has been available for more than a decade and has aided in shortening product development times and costs in the manufacturing sector. Stereolithography (SL), the most mature of RP technology, has primarily been used to build small to medium sized parts although there are largescale applications i.e. the automotive industry that uses “mammoth SLA”. Recent developments in SL have been aimed at increasing the speed of the additive process of most SL apparatus (SLA). Developments include the chemistry of photopolymer resins, integral-curing processes as opposed to vector-by-vector processes, and what is now called microstereolithography. Integral curing has been made possible by the advent of dynamic masking generators such as liquid crystal displays (LCDs) and digital micromirror devices (DMDs). Much of the theory for this new layering process has been applied to the micro-scale and awaits application for medium to large sized parts. The Limaye Model was applied to a microstereolithography apparatus (µSLA) and used as a process planning method for curing dimensionally accurate micro parts. Examination of the results of this mathematical model shows an irradiance map simulating the irradiances on the resin surface. The light is expected to attenuate from the central axis according to a measured irradiance curve. Improvements can be made to the Limaye Model to make it applicable for the process planning of medium to large parts. It is the aim of this research to present an improved mathematical model of the Limaye Model, so that a given irradiance map will produce an evenly distributed irradiance and account for errors in the optical imaging system. It is hoped that the field of exposure of 200mm x 270mm or larger will be achieved.