GPU Production rendering ignores material reflection max depth when using metalness

[1funk]

If you use metalness on GPU, the material's max depth is being ignored

NOTE: I filed another bug related to this, where RT trace depth is still limiting GPU rendering, so I have set RT Trace depth to 24 to avoid this bug.

1. Load attached scene
2. Ctrl+click the green teapot in the vray toolbar to start a production GPU render

RESULT: The reflection under the cube is black. This is incorrect.

3. Click the blue teapot to start a production CPU render

RESULT: The reflection under the cube now uses the max depth correctly and looks redish


Here are the results side by side:
Left = GPU production render
Right = CPU production render

[boyan]

Hey, funk,

Thanks for the feedback. I've logged to our system and keep you posted about it. If you, turn off glossy fresnel when use metalness with GPU, you should get at least closed result to the previous one release.

Keep you posted about it.

Cheers,

[1funk]

Thanks Boyan.

I really don't think that's a good workaround.

Turning off glossy fresnel is OK in my example scene because there is no roughness. Once you have a rough material, disabling glossy fresnel will give you bright edges

[boyan]

Well, funk

Can you check this workflow I think CPU and GPU results are close?

[1funk]

Your'e using quite glossy materials (0.8 and 1.0) where the results of "glossy fresnel" arent as obvious.

The rougher a material gets (try glossiness of 0), the more you'll see the bright edges. This is why glossy fresnel was added to V-Ray... to prevent the bright edges.

If you are using a texture in the glossiness slot, to create a material with smooth and rough areas (eg a metal where parts of it were sanded down with sandpaper), then the rough parts will have brighter fresnel edges (it looks similar to dust)

[boyan]

Well, You can enable the option in case you should use textures or high roughness materials to avoid the effect on edges.

Cheers,

[1funk]

That just get us back to the original bug where max depth isn't working correctly.

While having a higher roughness does hide the bug a little, it's still obvious you are missing additional reflection bounces because the rough reflection is dark.

[vladimir.nedev]

This issue is fixed in the latest nightly builds.
Both the 4.12.02 and the 4.20.90 builds.

Greetings,
Vladimir Nedev

[1funk]

Thanks vladimir.nedev