In predictive engineering for polymer processes, the proper prediction of material microstructure from known processing conditions and constituent material properties is a critical step forward properly predicting bulk properties in the finished composite. Operating within the context of natural-fiber reinforced thermoplastics, this investigation concentrates on the prediction of the local mechanical properties of an injection molded part. To realize this, the Autodesk Simulation Moldflow Insight 2014 software has been used. In this software, a fiber breakage algorithm for the polymer flow inside the mold is available. For the local fiber orientation, the anisotropy rotary diffusion-reduced strain closure have been used which is typical for fibers longer than 2mm. Using well known micro mechanic formulas allow to combine the local fiber length with the local orientation into local mechanical properties. Different experiments were performed using an own made flax-PP compound to compare the measured data with the numerical simulation results. To feed the numerical simulation software with material data, reverse engineering has been applied for both rheological and mechanical data for this kind of material based on tests for simple geometries (tensile test bar). In this investigation, initially, tensile tests and 3 point bending tests are considered. Using the appropriate settings for the different experiments, good predictions of the local mechanical properties are obtained. Finally, the obtained material data is used to model the mechanical behavior of an industrial part to illustrate the wider applicability of the material data and the numerical modelling.