Corona would be much easier to use for lighting designers if you applied IES files as they were intended. When I bring in an IES file, the performance I get should provide the number of emitted lumens as well as the candela distribution contained within the IES file. The size of the luminous area is contained within the IES file and it would be helpful if it was populated into a rectangle or disk based on the shape specified in the file. The problem is that a user needs to create this shape themselves in the command window and the problem is that Corona then alters the intensity of the IES file based on the adjustments to the physical size. In most cases, changing dimensions and shape to the size required scales the intensity distribution and therefore makes the intensity distribution incorrect. It would be helpful if changes to size resulted in NO change to the luminaire output - the distribution and lumens emitted would be the same. If, however, the user wanted the output to be changed, they could go to the entry for lumens and double the lumens, for example, if that was what they wanted. Since 99% percent of the time, the output desired is what is in the IES file, it makes sense to maintain the photometric performance described in the file, particularly since the luminous area dimensions listed in the file are not pulled into the Corona light object. As is, the user needs to call up the IES file in another tool that shows them the emitted lumens and the dimensions so these values can be input into Corona via the command panel.
These changes are a suggested workflow to provide the most accurate results and to save time for the user. Most users are likely unaware of these issues with how IES files are being addressed by Corona and therefore get inaccurate results as luminaire output levels are either increased or decreased when the user adjusts the source size or shape.
Submitted on AHA Ideas (CMAX-I-293).