Maya for 3D Printing - Rapid Prototyping
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# 1 26-01-2017 , 11:21 AM
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Arnold Renderer - Glass Transparency Issue

Hi,

Just switched over to Maya 2017 and started playing around with the Arnold Renderer. Absolutely loving it so far, however I seem to be having a problem creating glass with correct transparency. I am quite confident that my material is set up correctly, I have also unchecked the Opaque option for the mesh I want to see through.

My initial reaction was that perhaps I am using too much reflection, however turning it down does not solve anything.

The material in the Hypershade is looking correct.
user added image
user added image


Unchecked Opaque option for mesh.
user added image


I have set up a red box as a test object to more clearly see the transparency issue.
user added image


Transparency not looking correct. It only reflects the backside of the room. You can also see that I am having the exact same issue with the windows on the left hand side. They are letting light pass through, however I can't see the SkyShader outside.
user added image


Here is an example where I have disabled the visibility of the window plane - the background outside is clearly there - however for some reason I cannot see it through the glass.
user added image


Is there anything I need to do differently when modelling for the Arnold Renderer? Or perhaps a setting in the Render Options that I am not aware of?

Apologies if this has been asked before, I couldn't find anything relating to the exact problem I am experiencing. The tutorials I have watched online seem to create glass in the same way without any issues, so I am at a loss trying to figure out what it is.

I am running Maya 2017 on Win8.1 64 bit with an i7 4790 and GTX745. Let me know if you need any other information.


Thank you!

# 2 26-01-2017 , 01:04 PM
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It looks like the objects surface normals are facing the wrong direction. A quick and dirty way of telling is to uncheck "two sided lighting" in your panel's "lighting" menu (I keep this off for this very reason). It beats showing the actual normals (Display>Polygons>Face Normals) and having to fiddle with their display size because they're poking through everything and too messy looking to be useful lol. You can reverse the surface normals by selecting the object(s) or affected faces and going to Mesh Display>Reverse.


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# 3 26-01-2017 , 02:38 PM
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Thanks Genny! I checked the normals and they were facing the correct way. I think, however, I have managed to find the culprit. My refraction ray depth in the render settings was only set to 2. Increasing it seems to have fixed the problem.

Thanks anyways though!

# 4 26-01-2017 , 02:56 PM
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Ok, so the ray depth solved the problem with the wine glass and transparency. However, I am still having problems seeing my SkyShader through the windows.

Here's a screenshot with the window planes switched off. The SkyShader is right there.
user added image


However as soon as I reactivate the planes with the glass material - it looks like this. And yes I have made sure to uncheck the Opaque option for the mesh - the light is still shining through I just can't actually see the shader outside.
user added image

Is there a setting I have to adjust to allow seeing the SkyShader through objects?

Again thanks.

# 5 26-01-2017 , 05:12 PM
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Figured it out. In the aiSky node under Render Stats the Visible in Refractions option was unchecked by default. Checking it solved the problem.

# 6 28-01-2017 , 02:58 AM
Gen's Avatar
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Nice! Thanks for sharing your solutions. user added image


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