Glass Shader Renders Black in Cycles #43029

New Issue

Rick Savage · 2014-12-26T21:17:36+01:00

Rick Savage commented

2014-12-26 21:17:36 +01:00

I have made a character but for some reason the eyes renders black in Cycles? Each eye consist of two spheres, the scalera and the lens (cornea). Both are joined together and use different materials. The lens uses the glass shader with the IOR set to 1.45 and transparent shadows is checked. The eyes and the head are parented to a simple rig. Let me point out that the glass shader works fine in cycles until I parent the object to rig or to another object then it turns black. I even tried replacing the glass shader with refraction and its still very dark.

Acer Aspire 5040
CPU: AMD Turion™ 64 ML-32/ML-34 processor or higher with 512 KB or 1 MB of L2 cache, supporting AMD PowerNow!™ technology and AMD HyperTransport™ technology
Core Logic Chipset
VIDEO: ATI RADEON® XPRESS 200M GPU RS482M
RAM 1GB of DDR333 MHz
LCD, 1280 x 800 pixel resolution
HDD: 120GB
OS: Windows Xp Sp3 Media Pro, 32bit

I have made a character but for some reason the eyes renders black in Cycles? Each eye consist of two spheres, the scalera and the lens (cornea). Both are joined together and use different materials. The lens uses the glass shader with the IOR set to 1.45 and transparent shadows is checked. The eyes and the head are parented to a simple rig. Let me point out that the glass shader works fine in cycles until I parent the object to rig or to another object then it turns black. I even tried replacing the glass shader with refraction and its still very dark. Acer Aspire 5040 CPU: AMD Turion™ 64 ML-32/ML-34 processor or higher with 512 KB or 1 MB of L2 cache, supporting AMD PowerNow!™ technology and AMD HyperTransport™ technology Core Logic Chipset VIDEO: ATI RADEON® XPRESS 200M GPU RS482M RAM 1GB of DDR333 MHz LCD, 1280 x 800 pixel resolution HDD: 120GB OS: Windows Xp Sp3 Media Pro, 32bit

Rick Savage commented

2014-12-26 21:17:36 +01:00

Changed status to: 'Open'

Rick Savage commented

2014-12-26 21:17:36 +01:00

Added subscriber: @RikSavage

Bastien Montagne commented

2014-12-26 21:19:10 +01:00

Added subscriber: @mont29

Bastien Montagne commented

2014-12-26 21:19:10 +01:00

Please always attach a .blend file to help reproducing the issue…

And I think I remember glass shader can be tricky to use in some cases? will let Cycles expert handle this, though.

Please always attach a .blend file to help reproducing the issue… And I think I remember glass shader can be tricky to use in some cases? will let Cycles expert handle this, though.

Rick Savage commented

2014-12-26 21:30:06 +01:00

I have also set light path to limited global illuminations then increased the transparency bounces to 10 and gloss to 8. I have tried turning the caustic off and on but it still looks dark. It has something to do with shadows.

Rick Savage commented

2014-12-26 21:32:17 +01:00

Okay I will attach the file tomorrow afternoon since I am currenly using a mobile device.

Rick Savage commented

2014-12-27 05:50:34 +01:00

Turns out the refraction caustics was unchecked though im not sure why that would matter but it becomes clear whenever enable it. Now the reflections looks strange.

A good idea would be the add a caustics option directly onto the glass shader. Makes life easier.

Turns out the refraction caustics was unchecked though im not sure why that would matter but it becomes clear whenever enable it. Now the reflections looks strange. A good idea would be the add a caustics option directly onto the glass shader. Makes life easier.

Thomas Dinges commented

2014-12-28 14:05:09 +01:00

Added subscriber: @ThomasDinges

Thomas Dinges commented

2014-12-28 14:05:09 +01:00

Please upload an example file if you think there is a bug or I have to close this report.

Rick Savage commented

2014-12-29 23:37:08 +01:00

http://www.flipdrive.com/apps/mydrive/download?file=%2FKatie-Blackeyes.zip

Aaron Carlisle commented

2014-12-30 02:02:42 +01:00

Added subscriber: @Blendify

Aaron Carlisle commented

2014-12-30 17:37:06 +01:00

@RikSavage can you use a more common way of uploading a file, a way that does not require making a account for something. this saves our time

Rick Savage commented

2014-12-30 20:48:03 +01:00

Sorry for the mixup but I tried to send the file directly to the cloud from my mobile device but it said that I must drag and drop it into the textbox. The problem is Androids D&D doesnt seem to work between pages. I tried copy&paste but no dice. So naturally I had the find an alternative method.

Rick Savage commented

2014-12-30 21:19:53 +01:00

Here is an alternative link.

www.pasteall.org/blend/33601

Here is an alternative link. www.pasteall.org/blend/33601

Aaron Carlisle commented

2014-12-30 22:13:28 +01:00

@RikSavage I dont know if this is a bug but there other shaders other then glass. if you change the glass node to a transparent node you have know trouble

Sergey Sharybin commented

2014-12-31 10:24:03 +01:00

Added subscriber: @Sergey

Sergey Sharybin commented

2014-12-31 10:24:03 +01:00

Reuploading file here so it's not being lost:Katie-01-Cycles-Blackeyes.zip

Now, i don;t have a quick answer why the interior of the eye doesn't receive enough light, could be any of those:

Issue in implementation of glass
Transition effects caused bu the fact that in this setup all the interiors are inside the glass instead of eye having a hull
Issue with integrator which isn't perfect for caustics and so.
Loads of bounces required to the light to properly escape the eye (for secondary rays)

The setup will likely be quite noisy anyway, so considering http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Reducing_Noise#Glass_and_Transparent_Shadows is a good idea imo. It also makes your eye (well, not your but the character's you're working on) looking more or less expected.

I'll check what's exactly happening with light paths in this setup later.

Reuploading file here so it's not being lost:[Katie-01-Cycles-Blackeyes.zip](https://archive.blender.org/developer/F134398/Katie-01-Cycles-Blackeyes.zip) Now, i don;t have a quick answer why the interior of the eye doesn't receive enough light, could be any of those: - Issue in implementation of glass - Transition effects caused bu the fact that in this setup all the interiors are inside the glass instead of eye having a hull - Issue with integrator which isn't perfect for caustics and so. - Loads of bounces required to the light to properly escape the eye (for secondary rays) The setup will likely be quite noisy anyway, so considering http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Reducing_Noise#Glass_and_Transparent_Shadows is a good idea imo. It also makes your eye (well, not your but the character's you're working on) looking more or less expected. I'll check what's exactly happening with light paths in this setup later.

Sergey Sharybin self-assigned this 2014-12-31 10:24:13 +01:00

Sergey Sharybin commented

2015-01-21 12:20:24 +01:00

Changed status from 'Open' to: 'Archived'

Sergey Sharybin closed this issue

2015-01-21 12:20:24 +01:00

Sergey Sharybin commented

2015-01-21 12:20:24 +01:00

Had a closer look now. It's indeed just a whole bunch of bounces required to render eye in a way you expect it to be. Setting light paths settings to full global illumination helps there, but it's still not really enough for your case.

Instead of bumping bounces even further just use the trick suggested in the link above. You can also do it glass for camera rays and transparent for others to reduce noise even further but keep glossy highlights on the eye.

In any case, don't really consider it a bug. Just tricky situation for path tracer. Thanks for the report anyway.

Had a closer look now. It's indeed just a whole bunch of bounces required to render eye in a way you expect it to be. Setting light paths settings to full global illumination helps there, but it's still not really enough for your case. Instead of bumping bounces even further just use the trick suggested in the link above. You can also do it glass for camera rays and transparent for others to reduce noise even further but keep glossy highlights on the eye. In any case, don't really consider it a bug. Just tricky situation for path tracer. Thanks for the report anyway.

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Glass Shader Renders Black in Cycles #43029