Re: How do I get bloom to render in a transparent image?
Posted: Fri Aug 18, 2023 12:34 pm
Regarding the demonstration, it’s literally demo on the gif as what is shown is an actual Octane render with a VDB fire emission and Octane’s own bloom postFX applied on an exported EXR without any background (“alpha” encoded) and loaded in a compositing software. It’s really that straight forward.
The key is the associated “alpha” encoding aka “Premultiplied”, a term subject to avoidance.
The other factor is the compositor software. It has to properly interpret it. For that I’m using Fusion Standalone, the same can be done in Nuke and even in Octane's own built-in mini compositor.
I’d guess one the two is the culprit. I do plan to publish more in that, the last link I shared briefly goes over it.
I think I can share a zip with all files. I believe the VDB is a free one from the VDB website.
Edit: I forgot to mention that tiff allows it as well but not PNG, that’s also shown on the gif. The disgusting fire render is the PNG one. The imagery is evidently broken and not floating point, with an alpha wrongly encoded as “straight” (another term to avoid). EXR is the no brainer one to go for. TIFF for previews (typically non-linear encoded aka display conformed), not for compositing (as linearly floating point encoding is a must).
The key is the associated “alpha” encoding aka “Premultiplied”, a term subject to avoidance.
The other factor is the compositor software. It has to properly interpret it. For that I’m using Fusion Standalone, the same can be done in Nuke and even in Octane's own built-in mini compositor.
I’d guess one the two is the culprit. I do plan to publish more in that, the last link I shared briefly goes over it.
I think I can share a zip with all files. I believe the VDB is a free one from the VDB website.
Edit: I forgot to mention that tiff allows it as well but not PNG, that’s also shown on the gif. The disgusting fire render is the PNG one. The imagery is evidently broken and not floating point, with an alpha wrongly encoded as “straight” (another term to avoid). EXR is the no brainer one to go for. TIFF for previews (typically non-linear encoded aka display conformed), not for compositing (as linearly floating point encoding is a must).