Cycles volume rendering is too dark #41473

New Issue

David M · 2014-08-18T12:33:38+02:00

David M commented

2014-08-18 12:33:38 +02:00

System Information
Windows 7 x64
Geforce GTX 780

Blender Version
Broken: 2.71.4 7c9b8aa buildbot
Worked: 2.71 release

Short description of error
A dense white scattering material is expected to reflect almost all light, but appears
very dark in recent buildbot builds. The results of the 2.71 release seem much
closer to the expected result.

Exact steps for others to reproduce the error
Open the attached blend in a recent build, hit render.

**System Information** Windows 7 x64 Geforce GTX 780 **Blender Version** Broken: 2.71.4 7c9b8aa buildbot Worked: 2.71 release **Short description of error** A dense white scattering material is expected to reflect almost all light, but appears very dark in recent buildbot builds. The results of the 2.71 release seem much closer to the expected result. **Exact steps for others to reproduce the error** Open the attached blend in a recent build, hit render.

David M commented

2014-08-18 12:33:38 +02:00

Changed status to: 'Open'

David M commented

2014-08-18 12:33:38 +02:00

Added subscriber: @erwin94

David M commented

2014-08-18 12:34:57 +02:00

Attached file: volume_cycles_test.blend

Attached file: [volume_cycles_test.blend](https://archive.blender.org/developer/F104813/volume_cycles_test.blend)

David M commented

2014-08-18 12:40:18 +02:00

Okay, I was a little bit too quick with reporting this...

The results are the same for both versions, if I manually set the volume light path bounces
to the same value. The question then is, why does it load the file with a bounce value of 0
in 2.71.4 and 1 for 2.71?

Okay, I was a little bit too quick with reporting this... The results are the same for both versions, if I manually set the volume light path bounces to the same value. The question then is, why does it load the file with a bounce value of 0 in 2.71.4 and 1 for 2.71?

Sergey Sharybin self-assigned this 2014-08-18 13:42:01 +02:00

Sergey Sharybin commented

2014-08-18 13:42:01 +02:00

Added subscriber: @ThomasDinges

Sergey Sharybin commented

2014-08-18 13:42:01 +02:00

The default value for the bounce changed by @ThomasDinges, but i wouldn't expect the existing files to be changed.

Will check on making existing files to not change the final render result.

The default value for the bounce changed by @ThomasDinges, but i wouldn't expect the existing files to be changed. Will check on making existing files to not change the final render result.

Thomas Dinges commented

2014-08-18 15:38:37 +02:00

This is a limitation of Python properties as far as I know. The default was "1", if you never changed that yourself, it won't be saved into the blend file. So now it takes the new default which is 0. We had the same issue between 2.69 and 2.70, when we changed default bounces. See http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.70/Cycles "Backward compatibility breakage"

David M commented

2014-08-18 23:32:28 +02:00

Ah, okay. If fixing this is difficult I'm fine with closing this bug.
For any somewhat complex volumetric rendering scene I expect that value
has been touched, and I only found this in a simple test scene.

So I think accepting this breakage might be okay, but should
have a note in the release notes again.

Ah, okay. If fixing this is difficult I'm fine with closing this bug. For any somewhat complex volumetric rendering scene I expect that value has been touched, and I only found this in a simple test scene. So I think accepting this breakage might be okay, but should have a note in the release notes again.

blender-admin commented

2014-08-28 14:59:24 +02:00

This issue was referenced by 21a7433faa

This issue was referenced by 21a7433faafed266b48601d44d6aaf80ea66450b

Sergey Sharybin commented

2014-08-28 15:36:03 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2014-08-28 15:36:03 +02:00

Sergey Sharybin commented

2014-08-28 15:36:03 +02:00

Closed by commit 21a7433faa.

Closed by commit 21a7433faa.

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Cycles volume rendering is too dark #41473