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I am going to assume my question is dumb, but I'm having trouble with SSS and making a nice frosted translucent plastic. I have done the 2.02 patch and Rhino 4.0 SR7. This sample is using the stock MXM honey on the right and the left is the same material with roughness changed to 20 (original is 0). It seems that when I try to add roughness everything goes black. If I crank up the coef. to like 1500 then the material brightens up, but is very waxy and opaque.

Maybe I'm missing something?

Sorry, I was busy and forgot to respond to this when you originally posted about it on the Rhino forum. I am not seeing this behavior here using the standard 'sss' preview scene, so is it possibly related to this piece of geometry? What happens there if you import the sss_honey.mxm into the plugin, set the preview scene to 'sss', roughness to 20.0, and render the preview?

Yeah, the preview is fine (see jpg). I simplified the geometry and did another comparison. Somehow the multiple walls are acting strange with roughness. I can do roughness 0 and add a bump map and it seems to work OK, just not with roughness.

Looks pretty weird to me -- would it be possible for you to zip the .3dm and send it over (jeremy at nextlimit dot com) so I could take a look?

No problem - just sent it.

Thanks -- so you know, I'm not sure why it's behaving that way (it doesn't look right to me), but we're looking into it.

JD,

Apparently, based on another SSS question, it was stated that SSS is not functioning properly with emitters or sun. It is working only with image based lighting. I disabled my lights and assigned an HDRI and it rendered fine.

Now, can this be fixed. Uhhhh, no WHEN will this be fixed. I can imagine that SSS is difficult, but it seems to be an on again off again feature.

I didn't see anything particularly strange here and so forwarded your file on to the core developers. I had not tried to check out the emitters vs. IBL angle though, so thanks for posting back about that. I'll see what I can find out, status-wise.

adamwade wrote:Now, can this be fixed. Uhhhh, no WHEN will this be fixed. I can imagine that SSS is difficult, but it seems to be an on again off again feature.

This is fixed in 2.5