How to save an alpha channel in Rhino render window

Rendering
1

Hi Pascal
very simple question: how to save an alpha channel in Rhino render window (in order to handle the rendered picture later on in fx photoshop and insert the wished sky pic in stead of rhino background/environment)
although I 've saved as .png, Tif I get a non-transparent back ground … the alpha channel is always blacks !)
Regards,

1'_LI
1'_LI800×450 22.6 KB

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Hi @samerhanna,

Can you post your Rhino system information here please? Help -> System Information....

Do you have “Transparent background” checked in the Rendering panel?

In the render window, click the RGBA button to show transparency as a checkered pattern.

-David

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FWIW unfortunately Cycles, the engine behind Rhino Render, handles glass as on opaque material.

Maybe in the future I’ll be able to change that, but currently glass materials are ‘opaque’ from the renderer point of view.

'opaque' window
'opaque' window735×424 92.7 KB

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Hi David
the checkered is active when rendered but the output still with nontransparent background

This is my sys info
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my system info.txt (3.2 KB)

I found under rendering in properties window to the right ( Transparent Background not checked!) could it be the reason?
Regards
3

5

Hi Nathan
I don’t have glass in my windows at all … it’s too hot : )
so my question was quite simpler than alpha channel for glass material , regards

6

In that case you’ll have to make sure you see the groundplane so that it covers the entire window view. That is a current other shortcoming.

I hope to fix that in the future. It has been on my personal list for a long time, but I hadn’t made a youtrack issue for it yet. I did that now: RH-64483 Ensure background hit also gets alpha channel set when background is set to transparent.

7

Hi @nathanletwory is there any progress on this issue?
Yesterday searching for a solution I found that physically based materials can have alpha, but in regular glass material there is no way to solve the issue.
But then I found this

[Film options](Render glass with alpha transparency, cycles, blender 2.8 - #7 by tricotou - Materials and Textures - Blender Artists Community)

I don’t use blender but apparently this feature is not available for Us, right?

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No progress yet, and no direct access to Film settings either.

1 Like
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In the meantime, as a workaround, it is possible to use the legacy renderer to get the alpha.