Any way to render transparent glow/lighting?

[agabrys]

Good day,

I've been trying to figure this out for quite a while and can't seem to get the correct result.

I have a sphere with a ring around it with an Octane material (blackbody emission) for the light/glow. The glow only appears in front of the sphere if I have a, for example, a plane in the back with a shadow catcher or no object at all.

Now, I read somewhere (can't recall where) that using ACES in C4D/Octane will help. So I rendered a file with ACES, imported to After Effects and did the typically ACES setup and looks great. But then, when I go to convert ACES to RGB, the same thing happens where there is no glow where the transparent background appears. The thing is, it works in ACES but not during the conversion. Not sure if I'm doing something at this stage wrong or it's just physically not possible.

Any ideas?
Thanks,
Adrian

[elsksa]

Hi, to clarify some points regarding the color-pipeline/workflow:

Now, I read somewhere (can't recall where) that using ACES in C4D/Octane will help.

I would assume there was a misunderstanding on whatever that source was informing about. It is also plausible that the source is simply misinforming on the subject. ACES (as well as any other color pipeline/rendering transform) is irrelevant to transparency/"alpha". Typically, proper "alpha" requires EXR or TIFF as associated (aka "premultiplied") and an accordingly proper compositing that won't break it.

So I rendered a file with ACES, imported to After Effects and did the typically ACES setup and looks great. But then, when I go to convert ACES to RGB

This workflow/color-pipeline is technically incorrect. ACES pipeline goes from A to Z in the production stages, unless edge cases in controlled environment which isn't the present situation. Once ACES, all ACES. However, ACES as a look is faisible without the whole ACES pipeline. Octane introduced a hard-coded ACES ODT (checkbox in the Camera Imager) which doesn't require OCIO and is the same as applying the ACES sRGB ODT in post from a "Linear-sRGB" EXR input source.
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Some resources to clear out ambiguous thoughts:
• Fundamentals of offline rendering digital imaging & color-management
• “Display Rendering Transform”
• Octane ACES
• Octane Color Management
• ACES by Chris.B