Hi. I think you’re giving yourself unnecessary troubles. Here’s some things that’ll make life easier:
Don’t use the exposure control in Max’s environment panel. Use only Coronas exposure (panel or camera).
Don’t mix sun and HDRI. It’s not “wrong”, but it does require more knowledge and skills, and is harder to make “physically correct”. Use a HDRI only or a sun + corona sky.
Your HDRI seems to be set up wrong in the bitmap loader. I guess that “use real world scale” is activated in your preferences, giving some headache in max - your bitmap is to 1cm X 1cm in “size”, instead of 1 x 1 “tile”. To change this, you need to first select “map” mode, uncheck “real world”, and the set it back to “environment” and “spherical”.
You have physical exposure control installed in the environment panel and likely have your physical camera set to -6.0Ev in the physical camera properties.
It’s a free site with lots of high quality HDRIs. I’ve used some of them, and I only found one or two to be troublesome. I especially like the ones from Amsterdam, Berlin and Italy.
The result is really good. Thank your for your help !!
Do you use Megascan in 3Ds Max ?
I dont really know how set displacement (value) and if i have tu use CoronaDisplacementMod. Megascan no give indication about it.
Actually Megascan is one of the few content providers that includes extensive information with their products. You just need to open json file in text editor and search for height information. It might be that this info is also available in Bridge or Mixer.