Integrating 3D models with photography
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# 1 28-03-2011 , 12:41 AM
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Light pass through translucent object

I have a room that is lit up by outside light The light passes through a window with translucent curtains, but the light is completely blocked. I set the photon attribute to transmat but that allows all the light to pass through. I want to have some light to be blocked and most of it to pass through.

# 2 28-03-2011 , 07:58 PM
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I'm having a hard time completely understanding this problem. How is the room lit up when the light is completely blocked? What is being blocked, the direct light or indirect light (photons)? Also, a screen shot would help.


- Genny
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# 3 28-03-2011 , 08:58 PM
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I have a directional light and a Area light that emits photons into the room. The curtains are translucent/transparent, but they don't allow any light to pass through. I want some light to be passed through, kind of like a lighter shadow.

Here's a render.
user added image

Notice how the curtains are kind of see through but the shadow is completely black. It's blocking the photons, but I don't know how to let some through.


Last edited by Demon4231; 29-03-2011 at 12:47 AM.
# 4 28-03-2011 , 09:28 PM
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what are your raytrace settings?
i can see that you are using sun and sky (directional light) but what kind of photons are you talking about?

i guess it would be helpful to know the material attributes for the curtains. have you set any transparency?


Last edited by honestdom; 28-03-2011 at 09:33 PM.
# 5 28-03-2011 , 09:36 PM
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Directional Light (Sun and Sky)
Light Angle = 0.00
Shadow Rays = 20
Ray Depth Limit = 1


Render options
Reflections = 6
Refractions = 6
Max Trace Depth = 12

Shadows = 4
Reflection Blur Limit = 1
Refraction Blur Limit = 1

There's an area light in front of the window that emits photons. I have the light shader set to mia_portal_light.

As for the curtains they are a simple Lambert material with 0.347 Translucency and a little Transparency.

I'm also using Final Gather and Global Illumination


Last edited by Demon4231; 28-03-2011 at 09:49 PM.
# 6 29-03-2011 , 06:31 AM
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It seems to be the Maya standard shaders and GI. The transparency works fine til GI is turned on then the shadow turns solid so you're going to have to incorporate some MR shaders. The mia_material type should do just fine.


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