Reply To: Compositing Conundrum

OK slowly inching forward using the ellipse mask.

However the issue with this is that if I move the position of the object the ellipse mask position stays in the original position so this doesn’t work dynamically.

I expected to be able to set this up so I can render in multiple positions and the mask is dynamically updated based on the position so I don’t have to keep adjusting the ellipse mask. So… I suspect this does mean a cryptomatte or the dreaded maths nodes.

If we could stick to discussion the alpha approach for the moment so I know the limitations of what’s actually possible. I did suspect a cryptomatte might be the answer and went looking for the explanation in Core Compositing last night but couldn’t find it quickly and it had again become a very late night. I can’t really remember anything about Cryptomattes now. 

This was initially intended as a quick project just to have something original to use to get to grips with Substance. When I did the tyre and brought it back to Blender I thought it was worth doing a rim and then saw the issue I’d have with the final render before even doing the rim texturing. So as it seems ALWAYS happens this has unravelled into a brand new rabbithole of confusion and complexity but this struggle is where the learning lies.

I am so grateful for your help. I spent all last night trying to ChatGPT a solution but all that came out of it was me swearing