V-Ray for SketchUp tutorial - Materials - The Refraction Layer Refraction means the change of direction of a ray of light in passing at an angle from one medium to another. With V-Ray the refraction layer is used to create glass or translucent materials. Fernando Rentas, ASGVIS 3D Artist & Trainer, will explain how to use the refraction layer to create glass or translucency materials in this video tutorial.