Twilight Render User Forum

Hy,

I am trying to emulate a plastic surface that has a very thin area (about 0.4mm or less) and there is a light behind (LED). As we all know, there is no 100% opaque material in this world, so any material, starting with a certain thickness would transmit light at some level.
In my rendering i want that LED to transmit some light trough that very thin area, but the light to fade out as the thickness of material increases, until there is no light transmitted anymore.

So, that is what I need to achieve... a level of translucency/sss of a plastic that would result in what I described above.

Any help appreciated.

Thank you very much.

What i need is something like this (see the brighter logo more visible where the plastic is thinner)
Thanks

Sorry, I meant to respond earlier but got sidetracked.

SSS is definitely the hardest material to represent, and is also the one that takes the most time to render. Combine that with the fact that it can be simulated in very different ways by different render engines and it becomes quite a challenge.

I can't give you a silver bullet for it. I can say you should start with either the Translucent and / or the SSS templates. From there, it's just trial and error. Play with the alpha value (SSS does expose an alpha value) as that will have the most affect. From there you can look at the Absorption and Scatter. Two things to note: Scatter does nothing for Interior/Interior+ which does not support that feature, and you may get different results between other render methods (because some are optimized with a 'pseudo-translucency' while others have a 'real-translucency')

SSS is not well defined. It is probably worth it to do some systematic evaluation and post it on the forum (ie. X thickness at Y alpha, etc.) to be a baseline for users. It's not a commonly used material so it has been very low profile for a long time.

SSS material is what you want - remember it slows down rendering times significantly when the SSS material is a significant proportion of the rendered image.

Thank you very much! I will definitely try it, as I have to do that rendering in the following days. Do you think using grayscale bitmap in Transparency channel? I was just playing now a bit with SSS to see how it behaves. Indeed is rather unpredictable.

Thank you very much.