HDRI and Color Space

[naikku]

I am a bit confused about this matter. I haven't paid attention to the term "Color Space" when loading HDRI-files. REALLY. I haven't.
I just noticed that different Color Space-settings in the Vray HDRI loader give very different results.
I have been thinking many times that some of my renders are very flat.. And as I saw this difference, I started to think is there some rule when loading HDRI-files?
Corona settings says "Defines: Wide RGB" - So should, when loading HDRI-files to Vray HDRI-loader, should I check the Color Space to be "From 3dsmax" ?
I have been using inv gamma - because it is the default when loading files. And this here confuses me, why is it inv gamma (default) but when changed to sRGB or "From 3dsmax"
the rendering is much better.

I was up last night testing, I have the 6 studio HDRI-files from (cant download the files anymore, but they are very basic HDRI-setups):
http://www.cgrecord.net/2012/07/download-free-iray-studio-scene.html
As I switched from Mental Ray to Corona, I also started to use Vray HDRI-loader. So last night I tested, plane + some teapots + Corona interactive.
I made one Vray HDRI-loader and one basic 3dsmax bitmap-loader, both with the same file and no settings changed. As I dragged them to the enviroment slot,
the Corona Interactive showed very different results.

The file attached is the very first Color Space-test with a synth I modeled 2014. As I saw the results I started to think have I been rendering wrong for so long time :(
I have Gamma enabled 2.2 + materials/color selector checked too.

2nd thing which confuses me is:
I bought the Corona Interior Scenes from Evermotion, they render very nice always but they have bitmap output at 1.
When opening them in Photoshop they open dark. If I render and save as .png-file, should the bitmap output be at 1 as in the Evermotion-files. Normally I save without
adjusting anything and the files open in Photoshop as they are in the Corona VFB.

Suggestions? Links to tutorials? Books?

[Ondra]

You dont need to compensate or even think about the internal corona color space, because Corona automatically makes all the necessary conversions on input and output.

I am not sure about your case, but using different color space in this example could just mean you did some artistic control on the image and it looks "better" without actually being "more correct". What is correct depends on the way VrayHDRI treats input, and on how the image is saved - and I dont have that info, so I dont know ;)

[maru]

Using Vray loader (and any other Vray or any other renderer plugins) in Corona is not recommended! Vray loader is known to cause some troubles - for example flickering when UHD Cache is used. It is not expected to work flawlessly, and we cannot take responsibility for it.

As Ondrej said - changing the sRGB and inv gamma @ 1 settings might simply mean that gamma correction is different - maybe it is sRGB gamma (~2.2) vs gamma 1? Just use the Corona Bitmap and forget about any settings.

Also, you can get EXACTLY the same results as with the Vray loader using the Max's native Color Correction node, or using the "output" tab of bitmap.


About Evermotion scenes - output gamma should be set to 2.2. If it's different, it's a mistake, unless you are rendering with older version of 3ds Max and saving as 32-bit file.
See: https://coronarenderer.freshdesk.com/support/solutions/articles/5000515647
We will contact Evermotion about this.