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joie
04-20-2005, 10:19 AM
Hi there;

I was wondering how to achieve the light-passing-through-a-curtain effect in a window..., I usually do this with the translucency parameter of a normal MAYA lambert shader but it is very slow. So Iīd want to know what method do you use for this, because none of the MR Shaders has the translucency parameter, only the SSS shaders, but I canīt find the way to reproduce this effect.

I hope have explained myself well so you can understand what I mean.

Thank you in advance and sorry for my english.
joie
04-21-2005, 12:13 PM
No one?

OMG.

Well, maybe anyone can tell me how to tell the "sufaceLuminance" node to compute either direct and indirect lighting, is this possible?

Thankīs.
floze
04-21-2005, 02:18 PM
I'd use a misss for the curtain. Just experiment with the settings.
The surfaceLuminance simply returns the luminance (amount of light) hitting the specific surface point.
joie
04-21-2005, 03:05 PM
You are right.

But Surface luminance doesnīt compute incoming light the same way if attached to a simple MAYA lambert than a MR DGS shader, either using Final Gather, one donīt gathers FG but the other does. Thatīs my question was about...
floze
04-21-2005, 03:31 PM
Maybe this thread can clarify the difference of how luminance is being computed with dgs and maya shaders:

http://www.cgtalk.com/showthread.php?t=228118
joie
04-21-2005, 04:45 PM
Yes, I knew that, I discovered that the other day, I used a "surface luminance" node in a lambert and another with a DGS and they work totally diferent with FG, I mean DGS worked correctly, not the lambert wich computes only direct illumination.

My problem is that the attribute "tranlucency" is missing in all MR shaders, being only present in the Misss shaders.

But my curtain doesnīt have thickness so I suposse Misss shaders wonīt render well.

Any ideas?

P.S: Would a Mental Ray type "surface luminance" node compute FG the right way?
nojjy
04-21-2005, 05:54 PM
For simple translucency effects in mental ray try using BA_Flat from Binary Alchemy, found here:

http://www.binaryalchemy.de

A caveat I found using it is that it needs to be plugged into the shadow shader slot in addition to somewhere in your shading network.

Cheers,

Jon
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