This paper contains four contributions: (1) a physically plausible displacement layering operation based on the intuitive notions of material Thickness and Accumulation; (2) a universal pattern variation metric and control parameter called Size that simultaneously modifies the displaced pattern’s variation and magnitude, and which is used by the displacement layering operation for specifying and tracking the accumulated "bulk" produced by layered displacements; (3) an encapsulated Material object definition that specifies its BxDF response(s), displacement, and Thickness of application and desired level of displacement Accumulation; (4) a Material Layering node definition that allows encapsulated Material objects to be layered over one another in an easy to specify, intuitively controlled, yet physically plausible way simply by connecting them in the desired layering order.