Photoshop Sky

[glorybound]

I have always avoided adding my skies in post. I have tried everything, but I get that awful fringing of trees. There has to be a way to avoid this. I use Photoshop... Any clues?

[Pixelcon]

Render with a black background and use layer > 'remove black matte' instead of defringe.

[urbanite]

or untick sky visibility in vray light and render to exr. Alfa in the channel tab will do the trick.

[glorybound]

That's what I do, but I still get the fringe

or untick sky visibility in vray light and render to exr. Alfa in the channel tab will do the trick.

[glorybound]

I think I tried this, but I'll try again.

Render with a black background and use layer > 'remove black matte' instead of defringe.

[urbanite]

That's what I do, but I still get the fringe

Strange. Anti-aliased alfa should give you clean cut. How doe

[Svetlozar Draganov]

The Fringing defect will always appear regardless of the background color.
It is true that if the render is done on pure black background color the fringing is not so noticeable but it is still there.

This is because the output image is saved with pre-multiplied alpha, which means that every pixel which is anti-aliased with the background has some contribution from its color and this color becomes an issue when the image is mixed with another image.

There are two solutions here:

1.render to deep EXR - this of course will require compositing software that supports deep images which I believe is not the case with Photoshop.
2.render to TGA file with disabled Pre-Multiplied Alpha over black background - please note that you have to save the output image directly to the HDD via 3DSMax Render Output functionality, if you save it from the Max/V-Ray frame buffer the alpha will be always pre-multiplied. This method is not as good as the first one since the defect will be still visible but the result should be much better than files with pre-multiplied alpha.

[alexyork]

Another solution is to take your PSD with the sky comped in (with the fringing), turn off the render layer(s) so you're just seeing the background (sky etc.), then save this out as a fresh background map (in screen projection mode) for your render. Essentially you're going to then be rendering directly onto what your finished comp will look like, so the pixels around your trees and scene will be more or less the same as in the PSD.

You can also quickly select your alpha for the background and feather it by 1 or 2 pixels and expand the matte. This will often do the trick.

[zoranm]

Try this:

http://forums.chaosgroup.com/showthr...-Photoshop-Sky

z.

[glorybound]

just links back to this thread

Try this:

http://forums.chaosgroup.com/showthr...-Photoshop-Sky

z.

[zoranm]

Oops, sorry, my bad

Link: http://www.digitalartform.com/archiv...iting_pre.html

Z.

[glorybound]

I'll check it out, thanks!

[Pixelcon]

If you read the article it states at the bottom:

"UPDATE 3/23/2009:

So... LAYER > MATTING > REMOVE BLACK/WHITE MATTE is the official way to go."