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Translucent Material Question

Posted: Thu Nov 11, 2010 9:59 pm
by cornetjr
I have created a beautiful translucent material. The SSS is working great, shadows cast on the back of the material are displayed as expected, but light does not transmit through the material. Transmittence is maxed out, yet light does not pass through the material. SSS is working, any ideas what setting I might be missing. I will upload a screenshot and attache the material file tonight if that helps.

Thanks in advance for your help.

Re: Translucent Material Question

Posted: Fri Nov 12, 2010 1:49 am
by Bubbaloo
It would be helpful to see a render and material settings.

Re: Translucent Material Question

Posted: Sat Nov 13, 2010 7:21 pm
by cornetjr
Below is a rendering of the material in daylight. The problem is that when I render the material at night with a light behind it, light does not transmit through the material. I tested the light material with the translucent shell turned off at the lights emit beautifully. I have attached the material. Any advice would be helpful.

Image

Image

http://www.critiquethis.us/maxwell/tran ... an.mxm.zip

Re: Translucent Material Question

Posted: Sun Nov 14, 2010 2:13 am
by Half Life
Some questions for you first:

1) did you model the corian to 6mm or 12mm thickness in the model?

2) is the light source(s) the typical 15cm from the corian?

3) are we shooting for the matte, semigloss, or gloss finish?

Best,
Jason.

Re: Translucent Material Question

Posted: Sun Nov 14, 2010 2:22 am
by Half Life
try these settings as a 6mm gloss finish Corian (as it is single sided SSS you will not need to model thickness):

Image

It should render much faster.

Best,
Jason.

Re: Translucent Material Question

Posted: Sun Nov 14, 2010 2:53 am
by Fernando Tella
cornetjr wrote:Below is a rendering of the material in daylight. The problem is that when I render the material at night with a light behind it, light does not transmit through the material. I tested the light material with the translucent shell turned off at the lights emit beautifully. I have attached the material. Any advice would be helpful.
This gets my attention:
Roughness = 0
Reflectance 0 and 90 = black

I mean: I think the translucent part is ok, but you forgot about the not translucent one. Corian is not a black mirror, is it?

IMO (I'm still trying to get the trick of sss) in the daylight version it works ok because there's plenty of light surrounding the geometry so the object get's the color fast from sss component. On the other side, when the only light in the scene is inside the object the surface component shows much stronger than sss and in this case it is a black mirror.

Re: Translucent Material Question

Posted: Sun Nov 14, 2010 8:18 am
by itsallgoode9
From what I have been told and have tested, backlit SSS does not work well, it at all. If you're using SSS make sure to use an IBL otherwise noise will pretty much never clear up. I've been told that the IBL only for SSS is a known issue and is slated to be fixed in future versions of Maxwell. That came from the horse's mouth. As far as backlit SSS I have Ng heard any comments one way or another on that issue. As far as I've heard it is basically SSS doesn't play well with back lighting. From experience, I can tell you that is very true. All of the work I hav done is with product shots so the backlight is very close behind the object and not a larger piece which is what you are working with...so I have no experiences about that to comment on. I assume you're running into the same issues though

Re: Translucent Material Question

Posted: Sun Nov 14, 2010 12:50 pm
by tom
It's true current version has a performance drawback with emitters+sss. We're working hard to fix it soon, stay tuned.

Re: Translucent Material Question

Posted: Fri Dec 03, 2010 2:29 pm
by cornetjr
Half Life, your suggestions worked like a charm. I have to tweak the settings, but I will post results in a few days when they are fully baked. I was aware that SSS is kind of flaky, so I avoided it in the past, but in this project there was no avoiding it since it was the entire project.

Thanks again to everyone. This is why I have been using Maxwell for the past 6 years. Great community and the developers are actively involved in the forum.

Tom, you guys have to get SSS and emitters to jive asap! ;)

Re: Translucent Material Question

Posted: Sat Dec 04, 2010 1:23 am
by tom
cornetjr wrote:Thanks again to everyone. This is why I have been using Maxwell for the past 6 years. Great community and the developers are actively involved in the forum.

Tom, you guys have to get SSS and emitters to jive asap! ;)
Thanks! Something is about to happen soon, don't worry :)

Re: Translucent Material Question

Posted: Sat Dec 25, 2010 1:23 am
by tom
So, now? :)