Reply To: Piero: Cycles Hair Shape Settings in Blender 2.90

Okay, you’ve already figured out that turning of Shadows (in both feathers and bird) helps.

I’ve reduced it to the basics and gave the feathers a Transparent Shader and you were absolutely right @bkol that the lines are caused by the intersections.

With Shadows off:

compared to with Shadows on:

Increasing the resolution and the filter size also makes it a little better, but seeing that this is for an animation, it’s not worth the extra render times:

I’d actually sooner opt for a lower resolution, which also improves it a bit (maybe in combination with a denoiser ?)

Anyway, I’ve been trying things out and I didn’t find a way to completely remove those artefacts, sorry.