black borders around multipass Tweet

[rleuchovius]

Hi

I have lately started using Octane for c4d. Works great.

One thing I would love getting to work is the ability to take my render passes and merge them into one beauty looking exactly as the original.

This works except the black border around the object.

I have tried in vain to get it to work and would like some guidance.

I have attached the after effects project with the passes and an image to highlight the problem.

Please assist in the matter. I have tried a lot of settings in Octane but the black border persists.

tst_03 folder.zip

(14.34 MiB) Downloaded 241 times

[Silverwing]

I have checked it against what the standalone does. C4D Octane seems to not save "Unpremultiplied" or simply "Straight Alpha" files when saved through the Multipass Save Dialog. (At least not when saving to multiple files and not one multilayered EXR [Was not able to test that because I do not have Nuke etc])
I will write a bug report in the forum.

In the meantime you could save the passes through the C4D Save dialog. There the files have a "Straight Alpha" rim but miss the actual Alpha channel.
But you can use the alpha that comes with the beauty to cut it out from the Multipasses.

Thanks for the hint

Cheers,
Raphael

[slepy8]

what was your workflow rlechovius for generating those passes?

[Ferdinand13]

Hey guys,

Better late than never to this party

I had exactly the same issue lately, i.e. black lines building up on the edge of the Alpha, when I was compositing an Octane Multipass render in After Effects. FYI, I was rendering it all out from the Cinema 4D plugin into one Multipass EXR file.

I followed Raphael's advice about using the separate Beauty Pass's Alpha to cut out each multipass layer (using the Set Matte effect). However, there was still a 'residue' of the black line left even after that treatment.

After all, the issue is that for some reason the individual layers of the Multipass EXR file aren't using a Straight Alpha, or if they do, After Effects won't allow the use of the Interpret Footage dialogue to set it properly.

Therefore I was looking around on the internet, to find a way to 'interpret' the Alpha in the timeline. Lo and behold, I came across an old Creative Cow tutorial by grandmaster Aharon Rabinowitz, explaining After Effects' 'Remove Color Matting' effect.

https://library.creativecow.net/video_page.php?author_folder=rabinowitz_aharon&article_folder=CCQT_6_Remove_Color_MAtting

It pretty much describes the predicament I was facing, so I added the effect to the individual Multipass layers in my composition and - surprise - the black line disappeared.

So, bottom line, if Octane is once again delivering those nasty thin black or white outlines (an actual fix for that would be great of course), you can use the 'Remove Color Matting' effect to rectify it.

Mind you, not all Multipass layers seem to contribute to this. Neither Direct nor Indirect Diffuse seem to show any changes in the Alpha, when you use the effect on them. However, Direct/Indirect Reflection and Ambient definitely do.


Best, Ferdinand

[alecmaassen]

https://library.creativecow.net/video_page.php?author_folder=rabinowitz_aharon&article_folder=CCQT_6_Remove_Color_MAtting

It pretty much describes the predicament I was facing, so I added the effect to the individual Multipass layers in my composition and - surprise - the black line disappeared.

So, bottom line, if Octane is once again delivering those nasty thin black or white outlines (an actual fix for that would be great of course), you can use the 'Remove Color Matting' effect to rectify it.

Mind you, not all Multipass layers seem to contribute to this. Neither Direct nor Indirect Diffuse seem to show any changes in the Alpha, when you use the effect on them. However, Direct/Indirect Reflection and Ambient definitely do.


Best, Ferdinand

holy shat, i praise you.

[RSgraphics]

Strange. I haven't used layer passes yet because I haven't found any tutorials that i can successfully follow. Are you sure you understand the workflow? I couldn't imaging OTOY would just ignore this issue.