Vray: White line/contour render issue

[inuinu]

I've been struggling with this problem for a long time and perhaps there's someone here that had the same issue and managed to solve it.

 

When rendering alpha sequences - whether it's PNG, Targa or Tiff - I get a ca 1-2 pixel white line around the whole object.

 

I usually working with motion tracked footage so the lines becomes quite present when composing the CGI sequences with the film footage.

Been trying various settings with AA, Image sampler and Color mapping but nothing seems to solve it.

 

I'm composing in After Effects with Premultiplied Alpha and render in 3D studio Max.

What I usually do is to add a matte effect to the layer and remove the white line; which also removes some of the shadows that I would like to remain.

[utkudemir]

I have exactly same problem for a long time too it`s so annoying if somebody really know how to solve this problem it should be great.

Regards

[kumarsrimali]

You can use a trick to reduce most of the time remove the effect. That line comes from the background map you are using, maybe the environment map. To remove that white line, you can use less strong light for the environment map or you can also use custom color instead of pre-multiplied alpha in after effects. Use same color as your background map and it will remove the white line.

[Devin Johnston]

This problem has been around for years, sometimes it seems to be worse than others but I think it's a problem with the way Max or Vray saves out the alpha. To minimize it I set the background to pure black, this lessens the problem but doesn't fix it. I'd love to hear about a better way to deal with this.

[Francisco Penaloza]

From what I understand it is all about AA, usually we render about the same size that our final image, it really help if you can render bigger and the shrink your image to the final output. Also using a pure color, back most of the time, it will help with that bleeding area.

[James Vella]

1. After Effects - make sure your premult color is the same as your ambient light/hdri - this will remove fringing

 

2. Nuke - Premult after you have combined your passes - read the nuke manual on premulting so you dont combine your alpha channels (this adds 1px for every pass and adds up quick)

 

a video explanation would probably help;

[javierrueda]

Hi all

 

The solution (at least for still images) is just render with a pure black background. I guess that for animations you could render with separate passes.

 

The explanation is in this video:

 

 

Regards

[Chris MacDonald]

Can't you adjust the "choke" of an alpha in after effects too?

 

https://forums.creativecow.net/thread/2/975312

Edited September 27, 2016 by Macker