Translucency through surfaces with no thickness
Posted: Wed Jul 25, 2007 7:51 am
I know it is not phisycally correct, but it would be a must for keeping the polycount low on leaves, curtains....
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Translucency through surfaces with no thickness
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Posted: Wed Jul 25, 2007 2:25 pm
Do you mean SSS for thin geometry? I agree.
Posted: Wed Jul 25, 2007 3:58 pm
Right that.
Posted: Thu Jul 26, 2007 12:16 pm
Yes please, this would be very useful. Plz NL code thin-sheet sss 
/ Max
/ Max
Posted: Thu Jul 26, 2007 12:21 pm
Well, SSS (subsurface scattering) obviously happens under the surface of the object. If it doesn't have volume it doesn't have any effect... I think that what you want can be achieved with some transmittance and high roughness...
Edit:I'm making some tests and I'm wrong with the transmittance part, but sss is working for planes...
Re-edit: Now I think I understand what you mean; if I'm not wrong, sss works now like if the plane had infinite volume, right? I guess we need something in material editor that tells the core: "Hey, treat the object's faces which has this material applyed as if each face is two sided (out-in and in-out) with a thickness of .... 0,01mm"
Edit:I'm making some tests and I'm wrong with the transmittance part, but sss is working for planes...
Re-edit: Now I think I understand what you mean; if I'm not wrong, sss works now like if the plane had infinite volume, right? I guess we need something in material editor that tells the core: "Hey, treat the object's faces which has this material applyed as if each face is two sided (out-in and in-out) with a thickness of .... 0,01mm"
Posted: Thu Jul 26, 2007 2:36 pm
I meant right that.. 
I tried almost the same things you did but as you have spotted by yourself the results were not predictable... are you joining to this wish, then?
I tried almost the same things you did but as you have spotted by yourself the results were not predictable... are you joining to this wish, then?
Posted: Thu Jul 26, 2007 4:04 pm
Here are my tests:
Scene capture; the red box with the leaf is actually a 1cm thick box; the leaves are planar; box and leaves share the same material:
Render without SSS and transmittance rgb= 0,0,0:
Render without SSS and transmittance rgb= 0,3,0 (almost black very dark green):
Render with SSS and transmittance rgb= 0,3,0:
Render with SSS and transmittance rgb= 15,42,16 (dark green):
Render with SSS and transmittance rgb= 142,210,133 (very light green):
As we can see, Maxwell manages transmittance in planar objects as thickness=0 instead of infinite making them completely transparent with just a bit of transmittance, but with SSS it takes a planar as infinitely thick; we can see in the last one that the box renders as it should while the leaves of the palm scatters light a lot more.
Scene capture; the red box with the leaf is actually a 1cm thick box; the leaves are planar; box and leaves share the same material:
Render without SSS and transmittance rgb= 0,0,0:
Render without SSS and transmittance rgb= 0,3,0 (almost black very dark green):
Render with SSS and transmittance rgb= 0,3,0:
Render with SSS and transmittance rgb= 15,42,16 (dark green):
Render with SSS and transmittance rgb= 142,210,133 (very light green):
As we can see, Maxwell manages transmittance in planar objects as thickness=0 instead of infinite making them completely transparent with just a bit of transmittance, but with SSS it takes a planar as infinitely thick; we can see in the last one that the box renders as it should while the leaves of the palm scatters light a lot more.
Yes, I am. We need something in material editor to specify a "thin object thickness". A double sided option with thickness would be great.are you joining to this wish, then?
Posted: Fri Jul 27, 2007 10:48 am
Thanks a lot for the tests! Really useful and effective in showing what i meant.
Posted: Fri Jul 27, 2007 12:34 pm
Indigo has this for some time. Just a link so you can learn more about this simple feature
http://www.indigorenderer.com/joomla/fo ... php?t=1856
http://www.indigorenderer.com/joomla/fo ... php?t=1856