A novel 3-D hybrid model is presented for the prediction of propagation of radio waves in the presence of complex obstacles located on regular perfectly conducting terrain. The finite-difference time-domain (FDTD) method is implemented to model the source and obstacle regions, and the wave is then propagated by using the parabolic equation (PE) method-based algorithm. The source region contains all the complex obstacles and takes into consideration all the possible wave interactions in that region. The transition region between the FDTD domain and the PE domain is carefully treated in order to avoid numerical incompatibilities and to realize the time-/frequency-domain transition. The method is applied for different scenarios, starting with relatively simple obstacles like knife-edges for the verification and validation of the approach and then including more complex obstacles to the propagation medium. The results are compared to those obtained from full FDTD implementations of the same scenarios.