I want to get material whose opacity changes GRADUALLY from 0 to 1 based on object thickness.
Is this possible?
I want to achieve the effect as in the picture (granules embedded in the dense substance):
This is my try with VraySSS2 material:
I cant achieve the effect of 0 opacity where granules are near to the surface of the object
How can i do this?
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sorry for my English
if its not going to be animated how about just making an opacity map by hand ?
Can you use vray displacement clipping geometry using the Water level?
I think you can adjust the fog color in the refraction settings (Chaos: Industry-leading design and visualization software) or more involved you could use the FastSSS2 material (Chaos: Industry-leading design and visualization software - see Example #7).
I know that I can fake this effect.
But I ran into this problem many times.
I dont understand why VraySSS2 material cant simulate this effect.
When the thickness of the translucent object is close to zero, the material should be FULLY transparent, and when the thickness is increased transparency should GRADUALLY decrease.
I can reproduce something like that with VrayFog:
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sorry for my English
Maybe its more of an set up of max than material.. Have u checked ur metric units, scale, as well as the setting in vray about units and scale etc etc? Like use the max photometric scale and so on so on… or maybe just sample to low somewhere or model is badly modeled/bugged with wrong normals and so on… Dunno really 
VRaySSS2 can definitely simulate that effect. The example images show exactly the effect you’re looking for. There is an example of stairs lowering into a pool of water, the first step is almost completely visible and the lower the steps go the less you can see them. For VRayFastSS2, you have to set the “Single Scatter” option to "refractive"and you’ll have to adjust either the scale or the density. Like I said though, the refraction fog color can do it as well but will give a different look. You’ll need to play with the refractive fog color and multiplier a lot in order to get the effect you are looking for though as it can be quite sensitive.
I really tried. And I can not get VraySSS2 material with bright overall color, which is FULLY tarnsparent at close to zero depth…
Below test rendering and test max 2011 file.
If anyone can help me…
