Glossy bug - black edges around objects

[Zay]

Sometimes you don't notice it, but when one gets to know this bug, you can't help noticing it on images. And it's very annoying for me now. I hope this will be adressed in future builds.
In this test it was impossible for me to get a small amount of shiny surfaces without geting these black edges(Specular 0.0 - roughness 1.0). The 3 balls are low,medium and high poly balls.
It usually shows on curved objects.
If it is me that is doing something wrong, please let me know.

[ttaberna]

Darkened curves at grazing angles is a well known unbiased "issue" that some engines have adressed but as I am not a technician I don't know if this is posible to address in GPU engines.
So it is not you

[Zay]

I used LuxPose to LuxRender with the same test and it shows fine. Maybe it's a hardware/cuda thing?

[Felix]

It's a typical 'bug' in many glossy BRDF/reflectance models where light gets lost in reflections at grazing angles. In many render engines there are some kind of more or less good fixes, eg maxwell got it's glossy shader updated in version 2. Other engines, for example yafaray also suffer from this problem.

@Zay: Luxrender suffered from this this phenomenon for a long time, too. Some months ago they switched to a different glossy reflectance model (I think from Ashikmin to Schlick), but you can switch to the 'glossy-lossy' material and you'll still get energy loss.

[Zay]

You seem to know a great deal about this. I'm very new to LuxRender as LuxPose is just a pre alpha project so far, but could the same filtering/techniques be used in Octane? I don't know the limitations Octane might have that's why I ask.

[onebaretree]

I'm also getting this dark edge around glossy objects in my octane renders. It would be excellent if this is fixed in the next release.

[radiance]

Hi guys, we're fixing it
there's a more efficient way to do it than changing the BRDF, invented by an old friend.

Radiance