Antialiasing Black Line problem

[João Miguel Real]

Hi everyone,

im having an issue with the blending mode in Moho. I don´t know if anyone as come up with this, but every time i try diferente blending modes between diferente shapes, like overlay in this case, the render always brings a thin black line between the crossing of the shapes (see images below). I believe that this is caused by the alpha interpretation of the Antialiasing, because when i turn off the antialiasing the black line disappears but i lose the smoothness too. Has anyone come up with a solution for this problem? or you just render out every layer and do the compositing blending in other software like After Effects?



If anyone could help me with this one i would be very much obliged.

Best everyone,

João

[slowtiger]

Well, have you rendered out separate images and done a compositing test in AFX? I'd advise to first check.

[João Miguel Real]

Hi Slow,
Yes, the last time i add to apply blending modes in a project from Moho, i add to composite everything in AE in order to lose de black line. I was just wondering if anyone else add already came up with a solution for this, since its something thats has been talked here in forum. Its very time consuming going through AE, it would be much easier to export directly from Moho.
Thanks

[Greenlaw]

Hi,

I think the same or similar issue was discussed recently in this thread: Masked shape outline upon rendering

And I think you're correct, that he AA edges in the image or alpha are multiplying and creating a darker 'shadow' where they overlap. There are a few workarounds described in that thread.

Hope this helps.

[João Miguel Real]

Hi,

I think the same or similar issue was discussed recently in this thread: Masked shape outline upon rendering

And I think you're correct, that he AA edges in the image or alpha are multiplying and creating a darker 'shadow' where they overlap. There are a few workarounds described in that thread.

Hope this helps.

Hi Greenlaw,

I´ve read that post, although being a different issue, it relies on the same problem, the Alpha interpretation, i think it might be a question of Premultiplying the alpha ou keeping it Straight that Moho has. But its something the Tech team should try and have a look into it.

Thank you all anyway.

Best João

[João Miguel Real]

Hi everyone,

i think i have solved the problem of the antialiasing. What was happening, in my case, was the PNG compression of the Alpha channel was a bit sloppy, showing black line on the overlaying of the shapes. So after a series of experiments the most simple solution came up, final render all frames in Targa, although the size will be considerably higher, the quality is much better than PNG, especially the alpha channel. It will keep the alpha channel hidden after you render, so if you are going to do any compositing (in After effects for example), just turn the alpha channel ON within the files, and no lines from the antialiasing will show.

The same thing applies to other cases, like multiplying shadows etc.

So i think the problem is on the file type compression you use and not on Moho it self. Of course since Moho has PNG from default to preview the rendering the line will always show in preview, but if you final render with targa, your problem will be solved.

Hope this helps, it did for me at least.

Best to you all,

João Miguel Real

[Greenlaw]

That's surprising but good to kee[ in mind. Thanks for posting.

Quick question: did you try the PNG's rendered with Moho Exporter in AE as well? Just asking because the Preview render (Ctrl-R) in Moho is not exactly the same as the final render quality. I often see AA issues in the Preview render image that do not appear in the final export.

In general, I haven't had a problem compositing with Moho's PNG format itself in either Fusion or AE. I have seen a matte line when bringing the Moho rendered sequences into LightWave but I think that was just a Color Space issue fixed by changing how the import was interpreted. Maybe a similar issue when you imported to AE?