Finding correct settings for rendering layer masks

[SundancePioneer]

Dear Octane for C4D users,

I'm currently doing my first bunch of product renderings and I am really struggling to find the correct settings to render an accurate Layer Mask that i can use as an alpha channel when editing in Photoshop.

I found several Threads regarding a white fringe on the mask (it is a few pixels too big) - but none of the solutions seemed to work. As i will be working on tons of products, i really need to limit the amount of post-processing necessary.

White fringe too to mask being a few pixels too big always.

I'm using the most recent drivers for my 1070TI, Octane Render V4.02.1-R3.

My current Settings are as follows:

C4D - Render Settings

• C4D "Save" toggled to render flat image
  16bpc / Linear / Exporting as EXR (global setting)

Octane Rendering Settings (Render Passes)

• Render Buffer set to Float (linear)
  Render Passes enabled
  16bpc / Linear
  Show passes On
  Save Beauty OFF
  Multilayer File OFF
  Beauty Passes - Reflection, Refl. direct, Shadow
  Render Mask ID2 enabled (Layer i need the mask for)
  Info Passes - "Distributed Rays" selected, 128 max samples (unchanged)

Octane Settings

• Alpha Channel On
  Alpha Shadows On
  Keep Environment On
  Alpha Channel Toggled
  Partial Alpha & Pre-Multiplied Alpha both Off in CameraImager

When trying to use the "render Mask" File in Photoshop, the mask is too big (see picture attached).

I couldn't really find any setting that worked or gave me different results. If using render-masks is not the right tool for this job, i'd greatly appreciate if you suggested another method!
The reason i need the mask is that i need to seperate the contact shadow on the floor from the object itself, as floor shadows need to be toggled on/off later.

Any help in finding the correct settings is greatly appreciated!

Thanks in advance

Sundance

[bepeg4d]

Please, use Object Layer Color pass, and set the desired color with an Octane Object tag:
http://www.aoktar.com/octane/InfoPasses.html
ciao Beppe

[SundancePioneer]

Please, use Object Layer Color pass, and set the desired color with an Octane Object tag:

Hi Beppe,

thanks for your reply - i tried it, but i still get a white fringe. It's smaller now, but it's still not accurate. Anything else i can try?

Thanks in advance

Sundance

[mitchino]

I do a lot of product shots. I don’t bother with Octane for masks. Instead I create two standard c4d materials, one with only luminance (pure white) and one with no channels ticked (pure black). I apply these to my products/labels/lids/backgrounds etc and render using the standard render engine. The anti-aliasing settings must be set to best. I find this workflow incredibly versatile and fast, the masks render in seconds.

[SundancePioneer]

I do a lot of product shots. I don’t bother with Octane for masks. Instead I create two standard c4d materials, one with only luminance (pure white) and one with no channels ticked (pure black). I apply these to my products/labels/lids/backgrounds etc and render using the standard render engine. The anti-aliasing settings must be set to best. I find this workflow incredibly versatile and fast, the masks render in seconds.

Hi, Mitchino,

thanks for that, it sounds like a possible workaround - but if i understand you correctly, it is also one additional step to be done for rendering. I was hoping there might be a way to only have to render once per product, as i will be rendering a lot of different variations..

Is there a way to use your method "on the fly" without having to go back and re-render?

Thanks in advance!

Sundance

[Gregor.Zimmermann]

I'm not a hundred percent sure, if Mitchino's workaround is the best here, as it does not consider the Depth of Field/Motion Blur inside the octane camera. Or am I missing something here?

[SundancePioneer]

As a workaround, it is probably the easiest solution as i don't need DoF or Motion Blur. All i need is a clean alpha channel to use as a matte to seperate the hero object from anything else. The layer masks and Object Id passes do that, but not without a white fringe that i would have to remove manually each time..

[niestudio]

can you upload a simple scene with the setup that causes this?
I render products all the time and never see this.

[SundancePioneer]

can you upload a simple scene with the setup that causes this?
I render products all the time and never see this.

Sure thing - i'd be thrilled if you could take a look and share your expertise. Thanks in advance!

I have attached the simplified scene (dummy product with same textures and similar structure, since the original stuff is under NDA) with all the settings i currently use to render. I'm sure that i am just missing a setting somewhere, but i just can't find out which one it is. I have lowered the samples to speed up the test-renderings. (you might have to re-link the included HRDI file to get the same result)

RenderingSupport.zip

(1.25 MiB) Downloaded 132 times

I have also attached the problems in the resulting render again, using the settings from the file. (you can see the white spill on the edges - it happens when i try to use the Object ID Color pass as a mask in Photoshop - same thing in After Effects using it as a track matte. so it's unlikely to be a PS error):

Alpha Problem

Thank a lot for your kind help!

Greetings

Sundance

[niestudio]

Perhaps you can upload a cropped version of your photoshop file.
It looks to me like your mixup is there rather than your render.