We present a deterministic model of radio wave propagation based on radiance transfers. Our model uses radiosity techniques to determine facet-to-facet specular reflections according to a three-dimensional building description. The model contains two main components. First, visibility between elements is determined and used to establish links that represent radiance transfers that include diffraction and free spece losses based on geometric approximations. Second links are used to define a transfer equation whose solution provides the transfer intereflections. The solution is obtained by using hierarchical techniques. The results of the model show good agreement with measurements made in urban areas.