Generates an image containing 32–bit floating-point data that can be used for analyzing the amount of light that falls on a surface perpendicular to its normal.
The illuminance data ignores material characteristics such as reflectance and transmittance.
Illuminance is not related to surface properties.
For best results, render with a renderer that supports 32–bit floating-point output and set the output format to PIC, HDR, or EXR. When using the scanline renderer or another renderer that doesn't support 32–bit floating-point output, set the Scale Factor parameter, which acts as a multiplier, to adjust the range of values for the output data.