Hmm, it looks like there are some issues with this setup indeed. Corona to this day have troubles with handling complex refractive materials, so it's best to keep it simple to avoid potential issues. I made your glass and label with single material and decal should be working correctly now. You will probably need to fix your UV mapping, or masks, since there are some spillovers here and there, but i think you should be able to handle that on your own.
Hi Romullus,
Thank you for taking the time to look into this. Yeah, Corona definitely has it quirks, especially when using it outside of the archviv space. Unfortunately, I have not found a lot of resources for people using Corona for product renders, and since Corona was mainly developed for archviz work, I am finding it difficult to use for projects like this.
That being said, I truly appreciate your effort and the solution you provided. Your setup is very similar to mine, with the exception of the label and glass roughness additions in the glass base roughness slot. I'm curious about their function – removing them doesn't seem to affect anything visually beyond making the black background darker. Would you be willing to share your thought process behind including them?
On another note, with this method, it seems there's no way to adjust the size of the black background itself. Ideally, I'd like it to be slightly smaller on all sides than the surrounding non-displaced glass, creating a thin border of clear glass around the black label. Is there a way to achieve this effect?
Also, I would like to add a texture to the black background label to give it a more realistic look. However, I suspect I'd need to use a completely different material, like a black paper texture bitmap, to replace the flat black I'm using now. But if I plug a texture like that into the refraction slot of the glass material (replacing the current bitmap), I'm unsure if the paper texture would actually show through in the render. Any suggestions on how to achieve a textured black label?