Opacity lines with GPU

[fabrice_barbey]

Hi all,
I want to render feathers, so I have a lot of polygons on top of each others with a feather-shape opacity map.
When rendering with CPU everything is fine
and with GPU it's 4 times faster but unwanted lines appear everywhere.

Anybody knows how to solve this (big) problem?

[hermit.crab]

Tested this on a simple scene and it does not happen, so it must be something specific. Mind if you attach (or send) a scene with a few feathers and the assets so we can troubleshoot?

[fabrice_barbey]

Yes, here's the scene.

[fixeighted]

Without having tested I'm guessing it's shadow bias again. Switch it to 0.0 and see if it helps. Too much wine has been imbibed here for me to look...will in the morning if you get no response sooner

[fabrice_barbey]

Sadly shadow bias doesnt fix it.

Here we can clearly see it's a polygons intersection bias problem.

[hermit.crab]

Thanks for the provided scene. It turns out the edges appear only if the overlapping objects are small enough. Try scaling the whole thing and you'll see, they'll disappear. I need to talk to the devs since I'm not sure if this is something expected.

EDIT: FYI. I logged an issue (internal bug-tracker id: VGPU-6526).

[fabrice_barbey]

You're right, making a 100X scaling on the test scene gets rid of the problem.
I'll try on the main scene but as it contains skinned characters it's not the easiest solution.