Cinema4D version 2020.2-RC5 (Release candicate) 23.12.2020

[aoktar]

@aoktar
BUG: Channel Inverter node and Color Correction node.

Channel inverter node does not work for normals.
For example, if I want to invert the green channel of the normal - first I have to split the channels and then use the inverter node on the green channel.
If I use the inverter of the color correction node after separation, it will not work either, only the Invert node works.

Channel Inverter node: X


Invert node: (OK)


Color Correction node: X

Thanks, there's nothing about me(plugin side). Your assumptions/expectation for the behavior of invert that can be correct or not. Nothing to do for changing it in plugin. Please put your report to standalone topic.

[lanklaf]

Thanks, there's nothing about me(plugin side). Your assumptions/expectation for the behavior of invert that can be correct or not. Nothing to do for changing it in plugin. Please put your report to standalone topic.

Ok

[Antoncromas]

No no. When the image rendered from the picture viewer its being saved with a wrong gamma. I had to go through the photoshop and invert gamma to .45 to match the image that is shown on the picture viewer.

OK detected the issue. It's a case when save passes with c4d save formats when you select sRGB colorspace. It still assumes saved images are linear. I'm fixing this part for RC6 builds

Thank you!

[aoktar]

No no. When the image rendered from the picture viewer its being saved with a wrong gamma. I had to go through the photoshop and invert gamma to .45 to match the image that is shown on the picture viewer.

OK detected the issue. It's a case when save passes with c4d save formats when you select sRGB colorspace. It still assumes saved images are linear. I'm fixing this part for RC6 builds

Thank you!

Released the RC6 build, could you please test it?

[lanklaf]

Thanks, there's nothing about me(plugin side). Your assumptions/expectation for the behavior of invert that can be correct or not. Nothing to do for changing it in plugin. Please put your report to standalone topic.

Works in RC6!!

[karl]

@aoktar, is it possible to add a LUT or use a camera response with OCIO enabled?
I know we now have to enable "forced tone mapping" for it to work, but it smooths out all the highlights and looks very strange:

OCIO sRGB

OCIO sRGB + force tone mapping


BTW, could you add the ability to import LUTs as a node in the AOV Node Editor?
We have a color grading node and a color node,
adding a LUT node will make it possible to render the "final" image without going to Photoshop.

P.S. 2020.2 is awesome!

The reason why "force tone mapping" does that to the highlights is because the built-in Octane tone mapping doesn't do proper HDR tone mapping like ACES does (I assume you're using an ACES OCIO config). Custom LUTs and camera response curves in Octane only map from a 0-1 range to a 0-1 range, and so highlights are clipped before applying them. That's why the "force tone mapping" option is disabled by default. The best way to achieve what you're trying to do would be to modify the OCIO config you're using to include the LUT/curve you want to use as an OCIO look, and then select that look when rendering. You could try to reduce the exposure to bring the highlights down, but using Octane's built-in tone mapping (especially in addition to ACES tone mapping) is unlikely to ever produce a result as good as using ACES tone mapping by itself.

[lanklaf]

The reason why "force tone mapping" does that to the highlights is because the built-in Octane tone mapping doesn't do proper HDR tone mapping like ACES does (I assume you're using an ACES OCIO config). Custom LUTs and camera response curves in Octane only map from a 0-1 range to a 0-1 range, and so highlights are clipped before applying them. That's why the "force tone mapping" option is disabled by default. The best way to achieve what you're trying to do would be to modify the OCIO config you're using to include the LUT/curve you want to use as an OCIO look, and then select that look when rendering. You could try to reduce the exposure to bring the highlights down, but using Octane's built-in tone mapping (especially in addition to ACES tone mapping) is unlikely to ever produce a result as good as using ACES tone mapping by itself.

Uh, okay, now I understand what's going on, thanks!
ACES is awesome, but I really miss the Custom LUT option.
OCIO Looks are a good alternative, but I have no idea how to create them.
Do you have information on how to convert .CUBE files (for sRGB / REC709) to OCIO LOOK files, to make them work with ACES in Octane?

[karl]

The reason why "force tone mapping" does that to the highlights is because the built-in Octane tone mapping doesn't do proper HDR tone mapping like ACES does (I assume you're using an ACES OCIO config). Custom LUTs and camera response curves in Octane only map from a 0-1 range to a 0-1 range, and so highlights are clipped before applying them. That's why the "force tone mapping" option is disabled by default. The best way to achieve what you're trying to do would be to modify the OCIO config you're using to include the LUT/curve you want to use as an OCIO look, and then select that look when rendering. You could try to reduce the exposure to bring the highlights down, but using Octane's built-in tone mapping (especially in addition to ACES tone mapping) is unlikely to ever produce a result as good as using ACES tone mapping by itself.

Uh, okay, now I understand what's going on, thanks!
ACES is awesome, but I really miss the Custom LUT option.
OCIO Looks are a good alternative, but I have no idea how to create them.
Do you have information on how to convert .CUBE files to OCIO LOOK files?

I'm not an expert, but based on this documentation, cube files are supported by OCIO. According to the documentation for looks, you should be able to just drop the LUT file into the luts directory of the OCIO config, and then add this to the bottom of the config.ocio file:

Code: Select all

looks:
  - !<Look>
    name: Name goes here
    process_space: Utility - Linear - sRGB
    transform: !<FileTransform> {src: lut_filename_goes_here.cube, interpolation: linear}

This worked for me when I tested it just now. Keep in mind that if the LUT you're using only has entries over a 0-1 range, the use of the LUT may clamp the highlights anyway.

[lanklaf]

This worked for me when I tested it just now. Keep in mind that if the LUT you're using only has entries over a 0-1 range, the use of the LUT may clamp the highlights anyway.

It works! But yes, the highlights are clamped.
Is there a way to apply the look AFTER converting from ACES to sRGB?
As we usually do in compositing software, applying a LUT on the rendered image.

OCIO Look:


Lut on Renderd file:

[karl]

This worked for me when I tested it just now. Keep in mind that if the LUT you're using only has entries over a 0-1 range, the use of the LUT may clamp the highlights anyway.

It works! But yes, the highlights are clamped.
Is there a way to apply the look AFTER converting from ACES to sRGB?
As we usually do in compositing software, applying a LUT on the rendered image.

I believe you would just change the process space in the look definition from "Utility - Linear - sRGB" to "Output - sRGB".