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Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: jjaz82 on 2018-10-05, 15:31:46

Title: exr problem 16bit clamped
Post by: jjaz82 on 2018-10-05, 15:31:46

hi everybody
lately I have this problem.
i saved my render in exr, half format , 16 bit and the highlights results clamped like example.
i have attached exr file, there is something wrong?
thank you in advanced
Nicola

Title: Re: exr problem 16bit clamped
Post by: TomG on 2018-10-05, 15:48:06

What are you opening in it with? I opened it in Photoshop using the EXR-IO plugin, and the RGB comes out as expected.

Title: Re: exr problem 16bit clamped
Post by: TomG on 2018-10-05, 15:50:03

Oh wait I see, this is opening it and then adjusting exposure - I thought that image was what you were getting on open :)

Title: Re: exr problem 16bit clamped
Post by: Juraj on 2018-10-05, 15:51:27

Quote from: TomG on 2018-10-05, 15:48:06

What are you opening in it with? I opened it in Photoshop using the EXR-IO plugin, and the RGB comes out as expected.

But he's not asking about that, he's asking where is the dynamic range :- ).

Jjaz, did you use Highlight Compression in framebuffer ? To retain dynamic range you need to keep everything as linear as possible.

Title: Re: exr problem 16bit clamped
Post by: jjaz82 on 2018-10-05, 16:28:47

yes, TomG, my exr do not have all dynamic range i needed, i also use EXR-IO.

@Juraj yes i used highlight compression .. i will chek if this is the problem

Title: Re: exr problem 16bit clamped
Post by: alexyork on 2018-10-05, 16:39:40

I wonder if this is the same as the old issue we've found sometimes that if you use anything other than 1.0 contrast in tone mapping it destroys all dynamic range in the EXR. test that and see. We never managed to find a consistent way to trigger this.

Title: Re: exr problem 16bit clamped
Post by: jjaz82 on 2018-10-05, 16:48:38

now i have all dynamic range.
thank you :)

Title: Re: exr problem 16bit clamped
Post by: alexyork on 2018-10-05, 16:49:52

Quote from: jjaz82 on 2018-10-05, 16:48:38

now i have all dynamic range.
thank you :)

What was the problem/solution?

Title: Re: exr problem 16bit clamped
Post by: jjaz82 on 2018-10-05, 16:53:22

if you use Highlight Compression, the output is clamped.
i set Highlight Compression to 1

Title: Re: exr problem 16bit clamped
Post by: maru on 2018-10-05, 17:10:57

Highlight compression (in Camera tab), or highlight clamping (in System tab)?

Title: Re: exr problem 16bit clamped
Post by: jjaz82 on 2018-10-05, 17:14:09

in system tab

Title: Re: exr problem 16bit clamped
Post by: Juraj on 2018-10-05, 17:16:36

Quote from: maru on 2018-10-05, 17:10:57

highlight clamping (in System tab)?

I wonder if anyone actually uses that, I would wager 99perc. of users aren't even aware something like that is there.

OP mentioned setting it to "1", which refers to compression, but answered you "system tab" where clamping is, but setting clamping to 1 is...well clamping.
So I think there is some mistake here :- )

Title: Re: exr problem 16bit clamped
Post by: maru on 2018-10-08, 15:16:32

Yeah, highlight clamping (in the system tab) is highlight clamping, so highlight clamping is expected.

Title: Re: exr problem 16bit clamped
Post by: Juraj on 2018-10-08, 15:22:58

But he solved his issue by "setting it to 1". Setting HighlightClamping to 1 would make the exact opposite, make it further clamped.

This is some language barrier, he is 100perc. talking about compression.

Just noticed Clamping doesn't have help rollout.

Title: Re: exr problem 16bit clamped
Post by: maru on 2018-10-08, 15:47:10

Yeah, my last post was semi-kidding.

Quote from: Juraj Talcik on 2018-10-08, 15:22:58

Just noticed Clamping doesn't have help rollout.

You mean this?