Three-dimensional (3D) photonic crystal exhibit direction-selective transmission with respect to the center frequency of the stop gap. As a model system, the stop gap of a 3D fcc inverted-opal photonic crystal is studied in the microwave regime in detail using 3D polyamide models. The difference in the direction-selective transmittance between crystals grown in two different high symmetry directions is experimentally shown and compared to numerical simulations.