Weak Reflections of Volume Scatter Anisotropy #44518

New Issue

Zauber Paracelsus · 2015-04-27T06:07:08+02:00

Zauber Paracelsus commented

2015-04-27 06:07:08 +02:00

System Information
64bit Manjaro Linux, kernel 3.19
GeForce GTX 650 Ti Boost, driver 346.59

Blender Version
Broken: 2.75-dev, hash bdf6393

Short description of error
When the Anisotropy setting is used with the Volume Scatter node, the volume effect appears stronger around light sources, and weaker away from them, resulting in a glare or halo around lamps. However, reflections on glossy surfaces show a much weaker halo/glare effect around reflected lamps, as is visible in the render below.

This occurs with both CPU and GPU mode. OSL mode was not tested, since it appears to mysteriously be unavailable on all official blender builds I have tried.

Exact steps for others to reproduce the error

Download and open the following .blend file: VolumeScatterAnisotropy_Reflections.blend
Render
The glare/halo around the emission mesh will be much smaller on the sphere, much like the render above.

**System Information** 64bit Manjaro Linux, kernel 3.19 GeForce GTX 650 Ti Boost, driver 346.59 **Blender Version** Broken: 2.75-dev, hash bdf6393 **Short description of error** When the Anisotropy setting is used with the Volume Scatter node, the volume effect appears stronger around light sources, and weaker away from them, resulting in a glare or halo around lamps. However, reflections on glossy surfaces show a much weaker halo/glare effect around reflected lamps, as is visible in the render below. ![VolumeScatterAnisotropy_ReflectionBugRender.png](https://archive.blender.org/developer/F167267/VolumeScatterAnisotropy_ReflectionBugRender.png) This occurs with both CPU and GPU mode. OSL mode was not tested, since it appears to mysteriously be unavailable on all official blender builds I have tried. **Exact steps for others to reproduce the error** 1) Download and open the following .blend file: [VolumeScatterAnisotropy_Reflections.blend](https://archive.blender.org/developer/F167270/VolumeScatterAnisotropy_Reflections.blend) 2) Render 3) The glare/halo around the emission mesh will be much smaller on the sphere, much like the render above.

Zauber Paracelsus commented

2015-04-27 06:07:08 +02:00

Changed status to: 'Open'

Zauber Paracelsus commented

2015-04-27 06:07:08 +02:00

Added subscriber: @ZauberParacelsus

Thomas Dinges commented

2015-04-27 16:39:40 +02:00

Added subscriber: @ThomasDinges

Thomas Dinges commented

2015-04-27 16:39:40 +02:00

With "official" I assume you mean builds from builder.blender.org? They should all have OSL enabled.

Zauber Paracelsus commented

2015-04-27 16:41:33 +02:00

@ThomasDinges: There was no OSL problem. It had simply been a while since I had reason to activate it, and I forgot that it was a checkbox under CPU mode, and mistakenly believed it to be in the device menu dropdown.

Sergey Sharybin commented

2015-04-28 10:45:20 +02:00

Changed status from 'Open' to: 'Archived'

Sergey Sharybin closed this issue

2015-04-28 10:45:20 +02:00

Sergey Sharybin self-assigned this 2015-04-28 10:45:20 +02:00

Sergey Sharybin commented

2015-04-28 10:45:20 +02:00

I'm not sure why you consider this a bug. Glossy reflection is already reflecting light in direction of camera, meaning increasing world's volume scatter anisotropy just prevents light to scatter "sideways", reducing the halo effect. And at the same time the spherical light source emits light in all directions, so increasing volume anisotropy doesn't affect on it's halo that much.

So thanks for the report, but i don't really see issue so far.

I'm not sure why you consider this a bug. Glossy reflection is already reflecting light in direction of camera, meaning increasing world's volume scatter anisotropy just prevents light to scatter "sideways", reducing the halo effect. And at the same time the spherical light source emits light in all directions, so increasing volume anisotropy doesn't affect on it's halo that much. So thanks for the report, but i don't really see issue so far.

Zauber Paracelsus commented

2015-04-28 15:22:53 +02:00

Okay. I guess I don't really understand what anisotropy does, then.

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Weak Reflections of Volume Scatter Anisotropy #44518