[osuire]

Hi folks,
I suppose I should be posting this in the "Maxwell V2" section of the forum, but I feel more at home here
Anyway, I am trying to figure out the proper material parameters to render membranes with single side SSS.
The result should look like this : http://www.box.net/shared/static/3go0on778g.jpg
It is a polyester fiber + PVC membrane.
From above (with direct sunlight) it is white and reflective with subtle self-cast shadows, but from beneath, light is scattered with a beige-ish tint.
I just can't seem to find the proper settings, so here's a few questions :
Does it make sense to have attenuation in such a thin material ?
Then if there is no attenuation, does the scattering suffice to get the proper color underneath ?
Any idea what the refraction Index of PVC is ?
Should I use a BDSM with high roughness + a BDSM with low roughness, or just a mediumly rough BDSM ?
What's the difference anyway ?

Help much appreciated to narrow down the number of variables to fiddle with

Cheers,

--
Olivier

[JDHill]

Hi Olivier, try this. It has three layers with one BSDF each. The base layer is a basic whitish rough layer; I seem to see some off-white in your picture, though that might also have alot to do with white balance in the photo. The other two layers are both thin sss, and are similar to each other, apart from Nd and transmittance. I didn't have a real strategy here and instead went by trial and error; I'm still not too familiar with thin sss, so there are probably better ways to accomplish this material, but at least this might give you one place to work from. I did some test renderings using a scene you sent me some time ago...I'll pm you with those, as I do not know if you would want them posted or not.