Basically, the system works by breaking down the cloth to the level of individual threads, modeling how each thread reflects light. Then, based on how those threads are stitched together in a material (velvet is different than polyester, and reflects light differently), the program simulates the cloth. Since the process is super-granular, the researchers say they can simulate any type of cloth--even if it doesn't really exist. (Silk plus polyester threaded with a shantung pattern? Sure!) To make that possible, the team examined threads under a microscope, examining and measuring how different materials and patterns reflected light.