Single phase amorphous polymeric materials and two-phase polymer liquid crystals (PLCs) have been created on the computer and their behavior simulated using molecular dynamics. An external force was applied on the material and its response computed along time. The influence of several parameters was investigated, such as the concentration of the rigid LC second phase and the existence of regions of different orientation across the thickness of the material. A simplified 3-region model, such as that used to model the skin-core structure resulting from injection molding, was used. The influence of the relative size of each region with different properties was determined. Thicker skin regions increase the rigidity of the material, due to their higher orientation in the direction of force application. The concentration of the reinforcing LC second phase has a similar effect, also resulting in a more brittle behavior. The simulations have provided a better understanding of these phenomena. A method for calculating the true stress during simulation of computer-generated materials (CGMs) is proposed. The true stress behavior was found to differ qualitatively from the engineering stress when the structure of the material allows for considerable changes in cross-sectional area at large-scale deformation. (C) 2004 Elsevier Ltd. All fights reserved.