Strange squares not rendering

[PGD]

I'm seeing these random squares not render properly with this scene. See the darker, noisier spots in the image attached.

In other views this is still the case, but different areas.

They still appear if I switch to Bucket mode too

I have reset Vray withing the scene - and updated to Vray 6 Update 1.1

If I run a material override with a basic grey vray material - all is ok.

Strange how it runs over several bits of geometry

[vladimir_krastev]

HI, thanks for posting. Could you send us the scene and assets trough our support contact form so we can review it? Please include a link to this thread in you e-mail.

[PGD]

Will do..

I see the render is ok with all the tree's switched off. Strange how the render is affected where the trees aren't in the image though.

I have tried hiding the tree's individally, and the forest trees.. all still creates this strange render.

The only thing which makes the render ok, is hiding the tree layer or deleting all of the trees in the scene.

What to do now?
Set about replacing all the placed trees? I have rendered with them many times but not seen this issue before

[Vizioen]

You should check for faulty materials on those trees, just select them and choose get materials from selected objects in the slate editor. For instance my render crashes when having an old raytrace map. There might be some funky things going on with the materials.

[PGD]

It's weird..

Checked the materials as you said, all seems fine to me.

Add a material override just to the trees, and the square happens - in a different spot!

[Vizioen]

You can always remove the used trees one by one (or in groups and then narrow it down) and see when the problems stop.

[Vizioen]

Did you try rendering with a different light source? I'm assuming you're using an HDRI in a domelight? Did you try a regular VraySun & Sky?

[urbanite]

Do you have denoiser applied?

[PGD]

I haven't tried with a different light no, but yes it is lit with HDRi.

Denoiser wasn't on for the image above, but it was for earlier images. Which is where I first noticed the issue.

Thing is I've rendered this scene many times already and it's been fine. Just this latest re-render throwing this issue up. Tree's have been the same throughout.

[Vizioen]

Did you try and merge in a new scene? That often fixes weird stuff.

[PGD]

Did you try and merge in a new scene? That often fixes weird stuff.

That sorted it!

Many thanks. Can't believe I didn't think of it, this used to be common practice years ago but a rare resort now. Thanks again for the suggestion