VrayMTLWrapper Shadow Flickering

[sebbiej]

Hi all,

I'm rendering a scene with Vray GPU v6.20.02. The scene is fairly basic, the shot is a camera move towards an actor that's standing in front of a real shelf and wall. I've got a few objects placed on a CG shelf with a HDRI and a Vray Rectangle light. There is a wall behind this shelf that has a MTL Wrapper on it to catch the shadows.

There doesn't seem to be any flickering on the objects themselves but the shadows on the wall are flickering like crazy. How can I fix this? It's for a really urgent job.

I'm rendering with Light Cache, Animation preset, 3000 Subdivs, use retrace threshold is on (set to 8 ), mode is set to single frame. I have tried with Brute Force but it is still visable, CPU rendering isn't an option as we have a couple of hefty GPUs but useless CPUs with a super tight deadline.

[stezza]

How is the wall built/textured, do you have any double polygons occupying the same space?

[sebbiej]

It's pretty basic. Maybe I need to up the polycount for it?

It's a plain white wall, so I've got a slightly off-white VrayMtl attached in to the MTL Wrapper with the following settings.

[stezza]

Normals pointing outwards?

[stezza]

Have you tried an objects property node instead?
Can you share just the walls and lights as a scene?

[sebbiej]

Normals are pointing outwards.

I'll try an objects property node now. Thank you, I hadn't thought of using that method! If that doesn't work I'll send a PM with the lights and walls, thank you for your time, Stezza!

[hermit.crab]

Could you send it to me, too (plus some illustration of the flickering)?

[hermit.crab]

Thanks for the provided scene, and good job stezza, for nailing the culprit - progressive sampler's animated noise pattern. Summary of the issue: VRayDome Light, Shadow Catcher, and Animated Noise Pattern yield flickering alpha shadows. This has been reported before, and it's logged in our internal tracker (ID: VMAX-6976). I'll ping the product manager about it.