Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: actrask on 2019-05-08, 16:23:15

Title: LUTs and render elements
Post by: actrask on 2019-05-08, 16:23:15

If I have a LUT set in the frame buffer and I save out the render elements, is the LUT applied to those render elements? Or only the beauty pass?

Title: Re: LUTs and render elements
Post by: actrask on 2019-05-08, 16:52:32

I just did a test and the answer is YES, if the LUT is enabled in the frame buffer, it will save the render elements with that LUT applied. I only tested this with direct, indirect, and reflect passes.

Title: Re: LUTs and render elements
Post by: davemahi on 2019-05-08, 20:48:56

I have found rendering elements with the LUT applied does not give you the correct result when you comp the passes back. It does save the LUT on the elements, but not in a way that can be put back together in comp, unless I am wrong??

Title: Re: LUTs and render elements
Post by: Njen on 2019-05-09, 06:47:14

This is correct. AOV's need to be linear to be able to comp them together properly. Unless you know why you are doing it, you should never apply a LUT to AOV's.

Title: Re: LUTs and render elements
Post by: actrask on 2019-05-10, 17:41:36

I had assumed that the LUT was only applied to the beauty pass, but after noticing my comp looked like it was double up LUTs I dug into it. So then does it apply sharpening/blurring to all the AOVs too?

Title: Re: LUTs and render elements
Post by: maru on 2019-05-16, 14:47:51

Hmm, I don't think LUTs should be applied to render elements. We will look into this.

Title: Re: LUTs and render elements
Post by: actrask on 2019-05-16, 16:12:20

Great, thank you! Please check about the sharpening/blurring being applied to the render elements too, that one is harder to test. Right now I just have it turned off in case it does, but it would be nice to know.

Title: Re: LUTs and render elements
Post by: davemahi on 2020-07-22, 18:53:57

Quote from: maru on 2019-05-16, 14:47:51

Hmm, I don't think LUTs should be applied to render elements. We will look into this.

Any updates on this?

Here is what I would like to happen.

1. Use a LUT and it only applies to your beauty pass, leaving your AOV's alone.

2. Use a LUT and it applies the LUT to the elements so when comp together reproduce the look of the beauty.

Title: Re: LUTs and render elements
Post by: maru on 2020-07-23, 17:57:43

Quote from: davemahi on 2020-07-22, 18:53:57

Quote from: maru on 2019-05-16, 14:47:51

Hmm, I don't think LUTs should be applied to render elements. We will look into this.

Any updates on this?

Here is what I would like to happen.

1. Use a LUT and it only applies to your beauty pass, leaving your AOV's alone.

2. Use a LUT and it applies the LUT to the elements so when comp together reproduce the look of the beauty.

This should be working as expected in V5 already.
If it doesn't can you please provide the exact render elements which:
- you would like to have the LUT applied but it's not there
- you don't want to have the LUT applied, but it's there

Thank you in advance.

Title: Re: LUTs and render elements
Post by: davemahi on 2020-07-24, 17:51:08

Im not sure how to answer that. If you use a LUT and render out Render Elements, each element gets the LUT applied, and when comped will not look like the Beauty pass.

What I would want to see is either the LUT is only applied to the Beauty pass, and the elements are spit out without the LUT.

Or..........

The LUT is applied to the elements in a way so that when composited back, it matches the beauty. (This may not be possible with how the LUTs are used I dont know).

Right now you can just test for yourself with you Benchmark scene. Render it with a LUT and all Essential Render Elements. Then comp them in Nuke to see the difference.