IES is a specific kind of light used especially in architectural vizualisations. In 3ds max those files, which discribe intensity of the light in 3d dimension, are loaded into photometric lights. As you probably know Maxwell doesn’t have its own lights - each light must be made by your own. When we have to make simply area light - it is an easy thing. We just create plane and assign light shader to it. BUt it is much harder with IES files. We can’t load them to Maxwell’s emiters - but...Maxwell is based on physics of natural light so lets try to make it not by IES files but rendering.