A sphere light simulates a spherical light to approximate light bulbs. The sphere light illuminates in all directions outwards from the light source as well as inwards so that it can be used a a dome light.
Small Sphere light lighting the scene
Sphere light surrounding the scene
Sphere lights also support IES description file. IES (Illuminating Engineering Society) is a standard file format that describes the distribution of light of real world light sources using actual measured data.
IES file are used to reproduce the behavior of real lights in rendering packages. You can freely download IES profiles from manufacturers' websites, such as Lithonia Lighting or Philips, Eclipse Lighting, Delta Light...
Example of an IES light
Viewing IES profile can be done using IES viewers. There are quite a few ones available such as for example: http://photometricviewer.com
|Enable IES||Enable/disable IES|
|IES Filename||Specify the filename of the IES|
|Mix||Mix between the sampling of the IES and sphere profile. 0.0 disables IES sampling whereas 1.0 only samples IES.|
|Interpolation Type||Set the type of interpolation used for the IES data.|
|Cone Angle Angular||Set the aperture of the spot.|
|Softness||Multiplier for the angular penumbra of the spot|
|Softness Exponent||Exponent used for the softness of the spot|
|Spot Scale||Scale of the spot angle|
|Light Power||Power in units homogenous to watts|