The ray effect in ray tracing method was analyzed and three new ray emitting methods for a surface element (method A, B and C) were presented. Numerical computations of viewfactors for three different typical configurations indicated that the proposed methods can significantly eliminate the ray effect. Compared with the conventional ray emitting method, the proposed methods, especially method C, can give much higher accuracy with less computer cost. In addition, the new method may have much wider range of applications.