Render Alpha channel all black

Hi guys, when I render an image and save as PNG with alpha the alpha is empty, so I checked the render dialog and it too shows a black alpha:

Is it a bug, or a strange, unintuitive setting I need to learn? :slight_smile:

Oh, man, you guys make rendering difficult…
I see I have to toggle the “transparent background” option in the render options.
That is not intuitive IMO and should neither be necessary.

It would be great if Rhino just render with this data and we should be able to just toggle it on and off in the Render Output dialog thingo prior to saving. Can you please consider that?


Copy to clipboard needs to respect ALPHA for it to be an effective tool, can that be added?

Hi Jorgen - Meaning, Alpha should always be there, and the saving part of the process would determine what the saved image has, correct?


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Spot on, I think we should be able to choose that when saving.
If PNG then the background is removed and if TIFF an alpha channel is added.
And if other fileformats are used these days (I haven’t really done pro rendering for a decade) then those should be adapted too.
I think that would make the power of alpha more accessible to the beginners too :slight_smile:

By the way, here is the quick composition in Photoshop. Background added to view in Rhino so perspecitve could be synced, rendered with alpha, composited in Photoshop and a forground with copies of the trees ++ added. (That way I can quickly replace the render layer with adjustments with out having to do anything with it. So adjustments to the design or lighting is done swiftly)

Thanks for adding alpha though, now please make it easy for all to use :slight_smile:

(Oh and have to mention, being able to quickly render a 20 megapixel image in 20 seconds with only 15 iterations and intel denoising is quite sweet…)

@Holo - so, after much back and forth with Jeff, the upshot is that this, as obvious as it is to you and me, is a bit more complicated - that is, the alpha is not necessarily written as a separate channel but as transparent pixels - (png) The transparent pixels are not written if transparent background is not requested - if they were then on save, if the alpha were not saved by the user, the rgba values in the image would need to be reverted - possible but bass-ackwards to the programmers…