opacity bug?

Started by Dune, November 11, 2021, 04:08:50 AM

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I used to be able to use the opacity of a default shader to get rid of all 'black masked' areas, and make an area of a plane or sphere completely transparent. But this seems to have changed, unless I overlook something forgotten in the years since I got it to work. One could make nice ice remains hovering over water or ice. It shows alright in the preview, but doesn't render that way. Can't find my old example, but it's in the forum somewhere.
Check this out. It only works if you attach the glass shader, but underlying gets only 25% of the detail (due to default subdivision setting, so that's to be overcome), ánd the ice sheet gets transparent, which is not what I wanted.

It also shows the method to get shore foam off a landmass, btw.


I did some tests with your file, and I found at least, that it's maybe not a shader bug, but some issue with the internal sphere object. I opened a new scene, created a sphere, applied a default shader with a PF connected to the opacity output, and found, that the black areas aren't transparent, but black.
I applied the same shader to an imported sphere, and the black was transparent. Maybe this helps.


Thanks Hannes. Then using a non-displacable sphere might work too. But that would lack real displacement. And I wonder what causes it to be different between imported and displacable sphere. Sphere object changed?

Due to new computer and all new installs I don't have old TG versions to test if it's indeed changed.

Polysphere doesn't work either.


Yeah I reported this a little bit ago. It works in 3D preview, just not actual renders. So I'd say bug.


BUG! Please, Matt :-*


It's the same issue as this:


If you can settle for turning off "Defer all shading" (and not using path tracing), that will allow the opacity to work. If you need either of those render modes, try using a non-displaceable object type such as a Card or an imported object.
Just because milk is white doesn't mean that clouds are made of milk.


Thanks Matt. I had the vague idea I had mentioned it before and you replied to it. I hope to keep it in mind this time ::)  I understand it won't or can't be fixed, so a card it'll be.