Removing the outer edges in mental ray rendered images
This issue is most evident when rendering an image with an alpha channel and then trying to use it in a compositing application.
Here is a default mental ray render layered on a gray background in Photoshop:
The dark edging is due to the “Premultiply” option in mental ray found in the render settings window Quality tab > Framebuffer:
To remove this outer edge you can either:
A. In your compositing application, use the option to remove the outer edge. For example, in Photoshop you can do the following:
Layer > Matting > Remove Black Matte
B. or disable the Premultiply option before rendering with mental ray
Both methods will remove the undesired outer edge.
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September 8th, 2009 at 1:54 pm
In composting you should always render on a black background and then you won’t have any fringing on the edges with premultiplied images.
March 14th, 2010 at 8:23 pm
HI it seems that when you render this in sgi(rgb) format it gives some noise artifact along the alpha edges. Could be my scene file but do look out for that. I am not sure if same problem would come with exr.
June 3rd, 2010 at 2:35 pm
This is great for stills, the photoshop method I mean, but is there a similar fix for, say, After Effects for an image sequence? Thanks in advance!
June 3rd, 2010 at 7:46 pm
I don’t use After Effects, but all comp. applications has this option.
Might be in a different name, try interprete footage.(I think that is the name in AE)
Check the option for the alpha channel.
June 12th, 2010 at 5:31 pm
Xcelentttttt
niceeeeeee tutorialll jeje