Milky transparent plastic material

[borge.lund@smartseal.no]

Hi,

I'm struggeling to make a "milky" transparent plastic material look realistic (actually a transparent polypropylene). Both edges and thick parts should appear milky white, not black (nor a very dark saturated color).

- Is there a way to make the max-depth color not black? (I think V-ray for 3D Studio Max has an option called "exit color" to solve this, but I cannot find it in V-Ray for Rhino.)
- Is it possible to create a white fog-effect?

BLu

[Micha_cg]

Re: Milky transparent plastic material

You could setup a transparent plastic material and play with refraction glossieness and an additional diffuse layer with a transparency amount. Or you use a SSS plastic, you can find some infos at the material tutorial.

[dalomar_cg]

Re: Milky transparent plastic material

The key is going to be balancing the transparency of the diffuse layer with the effect of the refraction layer. If you have translucency checked, make sure that you have double sided unchecked as that will make it black. Its really hard to make a completely white fog effect, and it might be a little easier to shift the color of the fog slightly. Also white or near white fog takes a bit more glossiness than other colors. Wouter's translucency tutorial is really good, ang that might be good to look through as well.

[borge.lund@smartseal.no]

Re: Milky transparent plastic material

Thanks for your replies. I've added a photo of what I'm trying to achieve (pic added to my profile...didn't know how to upload it else.)

I read Wouter's tutorial - very good by the way - but no matter how much I've been experimenting the closest I get are grey zones where I want them to be white.

I have played with the refraction glossiness, but I don't want the refractions to become too blurry, as the cap should appear clear, not frosted.

As far as I can understand, the options I'm missing seems to be these:
- white exit color
- white fog color

Micha, I'm not quite sure what you mean by "an additional diffuse layer with a transparency amount."

Thanks.

[Micha_cg]

Re: Milky transparent plastic material

I think you need:

- reflection layer with fresnel reflection
- diffuse layer that catch the light
- set diffuse layer transparency at middle grey or something you like so you can look through the material
- refraction layer only necessary for blur refraction effects

[dalomar_cg]

Re: Milky transparent plastic material

In order to post the image you've got to get it hosted some where, which is really easy. I use imageshack.us and its free and generates all the code you need. Basically the image location just goes between [img ][ /img] tags. As far as your material itself, just start testing things. As you saw from wouters tutorial, where you place the light is going to be important as well.

[martin1012]

Re: Milky transparent plastic material

I'm still testing in this direction too, early phase... currently I cannot continue cause there are big renderings batching ;D
I ended up at this stage:
double sided off
A) medium translucency:
-reflection layer fresnel
-no or transparent diffuse
-refractionlayer: IOR 1.15, fog color dark grey (40), multiplier 0.1, affect alpha, affect shadows
now the trick:
-emissive layer: white, transparency 230, multiplier 3...

B) thicker translucency:
it's the game between emissive and refraction layer:
-refractionlayer: IOR 1.15, fog black (4), multiplier 0.1, affect alpha, affect shadows
-emissive layer: white, transparency 230, multiplier 5.5

... to ad blurryness in the material: simply put the refraction layer gloss to 0.5 e.g.

to make things colored, here with the thicker material (B):
-refraction layer: as above, but the fog color is a very dark orange (R12G04B00)
-emissive: as above, but the color is the bright orange (R255G85B00)

to play with a more or less diffuse layer like micha suggested is an option too.

the transparency color in the refraction layer could be a chance to lighten up the "exit" color, at least that worked for me with a clear glass... in my tests it slowed the rendertimes a lot.

but actually I couldn't continue testing the material in different environments or in interaction with objects from a scene (the emissive layer should be sending out light in the scene, don't know if it's so strong that it works more like a light, and not only to brighten the very dark and dull fog color : )
perhaps some inspiration?
ciao,
martin