We'll do our best. Please consider that this goes deep into the engine, so it may require some time. Thanks for your patience.

Hi Toby,

thanks for the detailed report. We’ll definitely look into the issues with the Octane Render Viewport and try to address the regressions you’re seeing compared to Blender 4.5.5 / Octane 30.9.

Personally, I’d really like the Octane Viewport to become much better integrated into Blender’s ...

Great!

I've attached the addon.

You should find it in the Octane menu in the 3D View.

Just click on Fix All RGB Image Nodes after loading your scene.

I hope it helps.

The most important change is about the Color Space option in the RGB Image nodes. It should be set to Linear sRGB + Legacy Gamma to work properly.
By default is set to sRGB and probably that also happens when loading "old" projects.

I rember we "fixed" that already, but maybe we had some unwanted ...

There's something important to consider.
That viewport is there for debugging purpose; it shouldn't be used for "regular" work.
That said, we really need to be able to identify and track the exact steps to reproduce the issue for fixing it.

It looks like it only happens the first time I launch the preview after loading your scene.
And only when Blender and the Server have been just launched.
Also, it doesn't happen 100% of the times here.
Did you try to close and reopen the Octane Viewport?

Could you please send me a simple scene showing the issue?

Now it works. I think it mught be due to some kind of initialization problem. I just changed the preview pass to beauty before launching the preview, and now it always works, with any preview pass selected.
I could only reproduce it the very first time I tried.

Yeah, something's wrong. We'll check. Thanks!