General Light Properties

OpenGL. You can change exactly which lights you want Affect OpenGL applied to simply by deselecting this control on those lights. This button determines whether or not the selected light will illuminate objects in your OpenGL Layout. Be aware that OpenGL currently supports a maximum of eight lights. You may have Affect OpenGL activated for 20 lights, but only the eight brightest in the list will affect objects within Layout’s OpenGL View, unless you specify the eight lights you want OpenGL to use by disabling the Affect OpenGL switch in all the other lights. Note that this does not affect rendered images in any way but only whether the effects of the selected light are visible in Layout’s OpenGL View. Affect Caustics The Affect Caustics button can actually save you significant render time if you have enabled caustics in your scene because you can eliminate all the lights from caustics calculations except the specific ones involved in the caustic effect. What are caustics? In the real world, caustics are very similar to specularity, except that instead of the light intensifying toward the camera, it reflects off the surface and intensifies on another surface. Caustics is similar to radiosity in that it is light that is reflected off one surface onto another or focused by refraction onto another surface. The difference is that caustic light is focused and highly intensified to create a bright area of reflection or refraction.