sRGB image in Direct visiblility overide

[sprayer]

Recently switch to 3ds max 2025 and struggling with color management.
My question, how to make image in frame buffer not effected by 3ds max AcescCG tone mapping? Before i used Corona tonemap control node for that.
I am able to make material editor and viewport to show proper image but not for rendering.
Thanks

[maru]

If you are using the OCIO color management mode, then there is a view transform applied to your render. I don't think there is a way to render some objects with the transform and some without it (or the background).

I think the easiest solution here would be to switch to gamma 2.2 workflow.

[sprayer]

I thought about that. Thanks

Maybe it should be feature request?

[piotrus3333]

You need to tag all input textures with correct colour space so Corona can transform the data into your rendering colour space. In user contribution section there is “alternative ocio for 3dsMax” containing “aces sdr video” colour spaces. use one of those.

[maru]

@piotrus3333 what am I doing wrong? :)
1 - set custom config in 3ds Max and load your OCIO
2 - set global default view transform to ACES 1.0 SDR-video - this way we get identical result to the default 3ds Max OCIO color management setting
3 - load a .jpg bitmap and pick "ACES 1.0 SDR-video sRGB" as its color space
4 - render

Unfortunately, the bitmap I am using is still "tonemapped". For example sampling a pure white color gives RGB207.

[piotrus3333]

@piotrus3333 what am I doing wrong? :)
1 - set custom config in 3ds Max and load your OCIO
2 - set global default view transform to ACES 1.0 SDR-video - this way we get identical result to the default 3ds Max OCIO color management setting
3 - load a .jpg bitmap and pick "ACES 1.0 SDR-video sRGB" as its color space
4 - render

Unfortunately, the bitmap I am using is still "tonemapped". For example sampling a pure white color gives RGB207.

bug in CoronaBitmap node?
works as expected with OSL UberBitmap (texture is 0.0 for black and 1.0 or white):

[maru]

I tried with Max Bitmap too and I must be doing something wrong. Could you take a look if you have some spare time?

[maru]

With help from Piotrus3333 here is the best I was able to come up with:

1. Make sure you are NOT using the ACES OT operator in VFB > Post
2. Download Piotrus3333’s OCIO file from https://forum.corona-renderer.com/index.php?topic=44209.0 and load it in Rendering > Color Management > OCIO custom config file
3. Under „Displays and Views” check „Show Advanced Settings”
4. Uncheck the checkbox next to „Global Default”
5. Set the view transform for Global Default to „ACES 1.0 SDR-video” – at this point you should get exactly the same result in the VFB as with the default 3ds Max OCIO mode
6. Go to the material editor and add a „Bitmap Lookup” or „Uber Bitmap” OSL map and load your background image - for some reason we couldn't get it to work with Corona or Max Bitmaps
7. Set this OSL map as your directly visible background (alternatively you can use, for example, a Corona Light Mtl with intensity set to 1)
8. Select your OSL map and under „Color space” in its settings pick „ACES 1.0 – SDR Video sRGB”
You should end up with an image which looks ALMOST like without the ACES tonemapping. There are some small differences, though. For example, pure yellow should be RGB 255 255 0 while what we get is RGB 253 255 136. Other than that, pure RGB, cyan, magenta, black, and white are correct. An example photo also looks "very similar" to what you get in the windows photo viewer or Photoshop.

[piotrus3333]

you can see what happens to saturated colours transformed with inverted aces 1.3 display transform here: