Providing a suitable thermal condition for the paint to be cured is of important parameters in achieving a desired cure. Continuous radiation ovens are of widely used apparatuses in paint cure and coating industries. Designing of these ovens for curing bodies of complex geometries have become a challenge for many years. In the present study a designing method is introduced and advised because of its acceptable capabilities. This method is based on cure window criterion and applies gradient optimization technique. The time consumed for designing is tried to be decreased through this model. A significant part of the time of designing procedure usually devotes to calculation of the physical model and to the iterations of optimization procedure. In this regard, defining a proper objective function efficiently reduces the designing time. Procedure of finding an appropriate objective function has been comprehensively discussed in the present article. Capability of the proposed methods is then evaluated for a simple two dimensional geometry of an automobile.