Rendering false color illuminance (lux) values
Now that blender support IES lighting, it would be great it cycles could render false colors for illuminance values (lux) received by the surfaces. Or/and luminance (cd/m2). This is a very important feature for architectural lighting analysis, and would be a great addition to blender.
The perfect thing would be if it calculate daylight illuminance value for clear sky given sky characteristics...
5 Comments
I'm also interested in that potential feature. I would work on that but I have no experience on addons or whatever it needs to be done to develop that.
Excuse my ignorance: Is what you're asking different from selecting the "False Color" view transform under Color Management in the Render settings? It converts the output to the kind of false color used in cinematography to find the right exposure, with greens in the midtones, blues/blacks for underexposed/clipping and red/white for overexposure-white clipping
Hi, thanks for the answer! Well, visually it's similar. This option shows exposure values gradient. But this is not the illuminance values that hit the surface. The illuminance is the quantity of light that hit a certain point of a suface coming from all points of light and is measured in lux. Exposure is the brightness seen by a camera. False color is just a representation style that can represent any kind of value. * @g3ntile *
* @ugosantana * And maybe It can be normalized/derived from that info? Taking into account that exposure in cycles is a very idealized/abstract value, in the sense that aperture or f-speed does not affect the exposure, only the explicit exposure controls, and curves.
I don’t know how cycles does its calculations, but maybe there is information needed. Iluminance can be calculated by luminous intensity in a determined direction (given by the IES file) divided by the distance to the point squared.