Nested Dielectrics in production

[pingovanderb]

Long thread - big issue.
I am having challenges with Nested Dielectrics. My very real production example is the infamous beer, with bubbles, foam, and droplets on the glass. All of this is absolutely doable. The challenge comes when I wanna slap a logo on the glass and e.g. use a bump for very small droplets or condensation. I also only want the logo and condensation to only be on the outside of the glass, etc. I actually have this working now with overlap method and by assigning different texture variations to different poly groups. But this doesn't work with nested dielectrics. I know that in order for "ND" to calculate the materials need to be "single" and applied to closed surfaces. But the aforementioned beer glass material is near impossible to make into single material without UV unwrapping the whole glass and making some quite complicated map combinations or an insane node tree. So how could this be done? Suggestions:
A: I could make polygon groups and use those to color masks but as mentioned this is a super complicated workflow.
B: the ability to mix/blend materials with similar IOR without breaking the nested dielectrics. This is what works with overlap method (this works in other renders)
C: Uv sets and/or somehow using poly groups in the Octane material tree to limit texture boundaries (if this exist in Houdini, I can not find it)

I'll gladly supply a test file for you to see the issue, but putting a logo on the outside of a glass with water in, should be challenging enough and present the issue.

[bepeg4d]

Hi,
please post a screenshot of your material setup.
Here is a fast example of nested dielectric with different Specular priorities, and Material layer for the logo on the Glass:

ciao Beppe

[pingovanderb]

That's super interesting Beppe thx for the reply! I did try with Material layers but must have done something wrong. What's that end node? the glass? And how do you restrict the logo to the outside of the glass? Could you share that file?

R21 pls.

Best, Pingo

[pingovanderb]

Just noticing Beppe, that it looks like your example is producing an error. That dark refraction of the logo inside of the glass is exactly what goes wrong here - not supposed to look like that..

[bepeg4d]

Sorry, my mistake.
With Nested Dielectric, the liquid must have a lower Priority. On the left, nested dielectric option active with lower priority for liquid, and on the right, with nested dielectric option disabled:

Here is the c4doctane R21 scene file:

NestedDielectricLogo.zip

(232.04 KiB) Downloaded 150 times

And here is the .orbx scene:

NestedDielectricLogo.orbx

(4.98 MiB) Downloaded 132 times

ciao Beppe

[pingovanderb]

Thanks Beppe, looking forward to see how you cracked this.

Pingo