OOF: Finite Element Analysis of Microstructures
The physical width of the image (e.g. 6 meters, 2 microns) in units that are consistent with the specified material properties. You are free to scale elastic moduli and lengths anyway you choose, just remember that your answers must be rescaled if you want to compare to experimental values.
The physical height of the image cannot be specified independently from the width. It is assumed that the pixels are square.