This paper presents an innovative approach that offers both a precise modeling of the propagation environment and a reduced computational load taking advantage of a multi-resolution algorithm. In this approach, radiating sources are simulated as point sources and are thus obviously omnidirectional leading to an important limit of the method. This paper tackles this problem by introducing multi-point sources. A regularized radiation pattern synthesis is then proposed for modeling particular radiation patterns. This approach enhances the accuracy of the predictions while preserving fast calculation times