In one embodiment, a method is for rendering medical volumetric images from received volumetric data, using a cinematic rendering approach, based on a Monte Carlo path tracing algorithm (MCPT). The MCPT algorithm uses at least one microfacet-based bidirectional reflectance distribution function (BRDF) for computing a probability how light is reflected at an implicit surface which is used for shading the implicit surface. In one embodiment, the method includes detecting if a surface scatter event is triggered. If yes, the method includes modifying the computation of a local gradient in the BRDF by perturbing the respective received volumetric data by applying a noise function for simulating a roughness of the implicit surface; and shading the implicit surfaces for rendering the received volumetric data.