General Light Sources and Effects

Note: Not all effects are available for all General Light objects.
Surface Caustics: Achieves a Caustic effect on the illuminated surface.
Volume Caustics. Achieves a Caustic effect within the light beam itself.
Important: The Volume checkbox will have an effect only if you have chosen enabled the Volumetric option for the Visible Light parameter (Visible Light page of Light Settings):
Falloff - Reduce Energy over Distance: This is unchecked by default. If checked, you may not see the Caustic effect, if the light source is far enough away from the surface.
Glows are a type of over-exposure to light
Reflexes are lens reflections
Glow: Check this box and use the pop-up to choose a Glow style for your Lens Flare.
Reflexes: Check this box and use the pop-up to choose a Reflex style for your Lens Flare.
Use the Brightness slider to adjust the brightness of the Glow and/or Reflexes in the lens flare.
The Height/Width value express a proportion; changing this value will distort the shape of the effect (glow or reflex).
Use the Rotation parameter (enter a value in degrees) to rotate the Glow element.
Use Global Illumination: This is on by default. Global Illumination (GI) is a sophisticated method for achieving realistic lighting effects in your model. The algorithm simulates the effects of not just direct light sources, but indirect light effects - that is, inter-reflections caused by light rays bouncing off surfaces.
Ambient Illumination: Normally the brightness of a surface is determined by the angle at which a ray of light hits it. When Ambient Illumination is switched on, however, the angle does not matter. All surfaces are lit with the same intensity; this results in a much flatter look. Only the material color is considered in the lighting calculations.
Only Effects, No Illumination: With this option, just the visible light effect itself, plus any lens effect, will be shown. No objects are illuminated by the light source.
Illuminate One Direction Only: Check this if your rendering doesn’t need the light to illuminate the space in all directions. (Use the hostpots on the Show Illumination feedback lines in 2D and 3D to graphically adjust the direction.)
Only Shadow, No Illumination: Use this if you want the light object to only cast a shadow, without producing any illumination. This can be useful if your scene contains multiple lights, and you don’t need all the illumination for the scene.
Disregard Surface Transparency: Check this option to help minimize render times (e.g. for a test render).
Ignore Diffuse Channel: With this option, the color properties of an object are ignored by the light source; only specular surfacing is produced by the light. This can be useful for objects such as a golden signature, where you would like specular glints, but no lightening of the color properties. This also produces a more metallic effect.
Ignore Specular Channel: With this option, the light source produces no specular highlights on your scene’s objects. This can be useful if, for example, an object is lit from both sides by two light sources, producing too many shiny highlights. You can retain the lighting but reduce the highlights by using Ignore Specular Channel for one of the lights.