VrayMTLWrapper Shadow samples

[sebbiej]

Hi all,

I'm playing around a bit with some car visualisation (using an InsightVFX tutorial and an Audi model I had lying around), I'm having a bit of an issue with low shadow samples on the VrayMTLWrapper that I'm using as a shadow catcher on the floor. There are some screenshots below from my render showing the grainy shadows beneath the car. I've upped the samples really high to Sampes Limit of 5000 and a Noise Threshold of 0.005 so the car is super smooth, but the dirt pass and the floor aren't great.

How can I fix this?

Any crit on the render is appreciated too!

[hermit.crab]

I've upped the samples really high to Sampes Limit of 5000 and a Noise Threshold of 0.005 so the car is super smooth, but the dirt pass and the floor aren't great.

Sorry to say, that's a common issue with Shadow Catchers. To avoid excessive render times, your best bet is to use a VRayDenoiser to clean it up. As for the VRayDirt / VRayAO pass, there's a separate Subdivs parameter in either.

[stezza]

One thing that may help is to increase the AA filter size and maybe use Gaussian filter type.
also Min subdivs set to 8-10

[sebbiej]

Thank you for the replies, both! Shame to see that it is just a common issue. I'll give the denoiser and/or the AA filter alterations a try.

[sebbiej]

After a bit of playing with it, unfortunately, increasing the AA filter size with a Guassian filter doesn't have an affect on the shadow sampling on the MTLWrapper...

Denoiser does smooth out the shadow, but then it also smooths out the edges of what was a sharp shadow.