Milky White Plastic in Cycles (Help Needed)

Hello,

I’m trying to create the material for a plastic bottle with cycles and can’t really find a good solution. Here are two images for you to look at (3D-Model on the left - actual photo on the right).



The tricky part is that the bottle should be almost transparent in thin areas (blue dot on the 3D-model) and very opaque and milky white in thick areas (red dot on the 3D-model).

I’ve tried to work with the Absorbtion Node that is provided by the BlenderDiplom website (https://www.youtube.com/watch?v=qkqsx951gcg) but this version can only go darker or more saturated in thick areas and I’m not able to go towards white. I’ve also tried to use the Volume Absorbtion Node of Blender, but this has the same problem. It would be great if I had something like the Absorbtion Node Group to control the mix between two shaders. Plugging the Absorbtion Node into the Fac Node of the Mix Shader has no effect.

If possible, I would like to use a solution without SSS, because I’d like to render the scene using the GPU.

Maybe there is some Cycles expert out there who knows a solution.

Thanks in advance,
Andreas

Hello,

I’ve tried the suggestion. It’s similar to something I had before. Thsi sort of works, but it doesn’t really take into account the material thickness too well. It’s too milky in the center area and still too transparent in the thread area.


Cheers,
Andreas

Are you sure “red dot” and “blue dot” really are the same material on the real bottle?
And even if they are, who says that they need to be the same material in Blender, too? Just make those different materials and adapt the node setup for each until it looks about right…:wink:


You should use 2 different materials, one for the white part and other for the blue part. Is easier that way and you’ll save some time too :slight_smile:

You could reduce the amount of translucent - but throw some volume scatter or absorption into the node group too. The volumetric shaders factor in the thickness of the object (but they are slow).

Or - you could take a look at this tutorial which simulates volumetric absorption using the light path node.

Hello Moony,

I’ve already tried the absorption approach. This works well if you want to make thick areas darker, but doesn’t if you want to make them brighter.

It would be awesome if that color output could be used as a controller for mixing materials or affecting other values, but I don’t know if that is possible. Plugging the color output in the Fac input of the Mix Shader has no effect. Any ideas?

Cheers,
Andreas

Hello,

as I can’t come up with anything else I tried the method of combining two materials and it sort of works. Not the most elegant solution but fine for now. Maybe somebody can still come up with a method to blend two materials based on the thickness of the object.



Thanks for the suggestions so far,
Andreas