We use a 3D Radiative transfer model to perform diagnostic studies of the morphology of the stellar bars in spiral galaxies. The model galaxy is described by three axisymmetric components (a stellar disk, a dust disk and a stellar bulge) and one non-axisymmetric (a stellar bar). Using the unsharp masking technique, we reveal the morphological signatures of the bar component when changing various parameters (such as the inclination angle and the PA of the galaxy and the size of the bar). These signatures are then compared with real galaxy observations as well as orbital profiles of the disc galaxies.