This book describes the development and application of a method of virtual generation incorporated with post-processing image analysis that can be used to fabricate a virtual, two-dimensional microstructure of composite mixtures. In the generator, geometrical characteristics such as aggregate gradation, aggregate area fraction, angularity, orientation, and elongation are used to transform data from a three-dimensional image into a two-dimensional image.The generator can provide significant savings in time and cost, and it can also be used to improve current methods for the mechanical characterization of composite mixtures.