Problem when Compositing Transparent 3D Render using Multilayer EXR

[Arini R]

Hi all,

I'm learning to make composition in Affinity Photo for my 3D render of transparent object from Blender. My goal is to make the object recolorable just by adjusting the color in Affinity Photo. I separate my object elements using Cryptomatte pass in Blender compositing.

I make use of the Multilayer EXR output from Blender and open it in AP with using the Associate OpenEXR alpha channel option. I manage to make the composition results to be the same as the Blender render results with one tiny bit of miss. The results has a tiny noticeable outline as the attached image. It will disappear if I put a fill on the back of everything, but I need it to be smoothly transparent. I've tried compositing using PNG but it still there. 

Is this expected results? How do I get rid of it? Thanks in advance

[firstdefence]

@Arini R Any chance you could produce a sample/partial render multilayer exr file and upload it so we can take a look ourselves?

[Arini R]

44 minutes ago, firstdefence said:

@Arini R Any chance you could produce a sample/partial render multilayer exr file and upload it so we can take a look ourselves?

Sure, here is the sample .exr straight from Blender and the screenshot of layer arrangements that I'm using. M is Multiply and A is Add.

0002.exr

[firstdefence]

This is definitely something to do with Affinity Photo, I opened the file up in Adobe Photoshop CC and it resolves the image in a slightly different way where the edges are fringed more with a lighter colouring than the dark brown seen in Affinity Photo. While it looks better without a background if you place a dark background behind it you get to see the fringing. In Affinity Photo the fringing does seem to correspond to the background colouring.

I wonder if leaving the Background out or deleting the background in Blender and exporting might give a more favourable result.

Adobe Photoshop CC 

[Arini R]

4 hours ago, firstdefence said:

This is definitely something to do with Affinity Photo, I opened the file up in Adobe Photoshop CC and it resolves the image in a slightly different way where the edges are fringed more with a lighter colouring than the dark brown seen in Affinity Photo. While it looks better without a background if you place a dark background behind it you get to see the fringing. In Affinity Photo the fringing does seem to correspond to the background colouring.

I wonder if leaving the Background out or deleting the background in Blender and exporting might give a more favourable result.

Adobe Photoshop CC 

Thank you for taking the time checking the file @firstdefence

I don't have PS so I can't try it myself. I  tried on Krita and it has thinner line though.

The results is the same when I leaving the background out in Blender.

Some guys on Twitter point out that it has to do with premultiplied alpha and I have to try different approach for this to work on AP. 

I guess I have to tinker around a bit if I still want to use AP 😖

[davedev]

Uh, did you ever solve this? I'm having the same issue. I think. Attached is picture of my issue from Daz using exr canves vs. no canvases and composite render in daz.

[Arini R]

7 hours ago, davedev said:

Uh, did you ever solve this? I'm having the same issue. I think. Attached is picture of my issue from Daz using exr canves vs. no canvases and composite render in daz.

 

Hi, I manage to get rid of it by some help from Twitter. See the thread here

 

[davedev]

Ok. So not sure if I saw the answer on Twitter or elsewhere, but the recommendation was to enable all three exr options, Associate, Post divide, and perturbe,  in the Color Preferences which seems to work for me! See the attached screen grab.