Contents Materials » Optical Properties » VOP on SurfacePrint page VOP on Surface VOP on Surface allows Speos to simulate non-closed bodies with volume properties. This section contains the following topics:VOP on Surface OverviewVOP on Surface allows Speos to simulate non-closed bodies with volume properties.Creating a VOP on SurfaceThis procedure helps you define a non-closed body in a simulation to be considered as a VOP on Surface. « Creating Face Optical PropertiesVOP on Surface Overview »