Applications using sheet gaskets involve acids, corrosive chemicals, steam or mild caustics. Volumetric caustics can also be achieved by volumetric path tracing. It also supports caustics and physically correct simulation of global illumination employing photon maps. In practice, however, only the simulation of diffuse inter-reflection or caustics is called global illumination. Improvements included soft shadows, caustics, global illumination, and better atmosphere models. Several anisotropic wet etchants are available for silicon, all of them hot aqueous caustics. Some of them even support volumetric caustics. Similarly, for numerical methods one needs to avoid caustics (coordinate singularities). In computer graphics, most modern rendering systems support caustics. It has also shown promise in correctly rendering pathological situations with caustics. Rippling caustics are commonly formed when light shines through waves on a body of water. Spent caustics are malodorous wastewaters that are difficult to treat in conventional wastewater processes. It is related to the concept of caustics in geometric optics. Some examples of 3D ray-traced caustics can be found here. A common situation where caustics are visible is when light shines on a drinking glass.