Black pixels in rendered image

[Kevin Kipper]

Can someone help me identify what's causing these black pixels in this render? I have rendered this image as a full frame and also in slices.  In the slices the black pixels show up in different locations. 

Here are the render settings:
Pixel Filter: Mitchell-Netravali
Detail blending 1
Microvertix jittering On
Detail Jittering On
Max Threads 8
Subdiv cache 1600
Ray detail region = Detail in camera
Ray detail region padding 0
GI prepass padding 1
Gi relative detail 1
GI sample quality 10
GI blur radious 40

Thanks,

Kevin

[Tangled-Universe]

I suppose you render an animation given the high GI sampling/blur radius and detail blending?
If not, disabling detail blending will give you a great speed up, since you only need it for animations.

Anyway, I have seen some artefacts, but this is something new for me.
Looking at the terrain it looks quite displaced so my first guess would be to increase the displacement tolerance for the planet shader.
Default is 1, try 2, then 3 and then leave it.
(when you test-render this on single frames disable detail blending and GI pre-pass padding for much faster results)

It would be most useful if you could upload the .tgd of the terrain only so we can have a look.

Cheers,
Martin

[Kevin Kipper]

Thanks Martin.  I'm turning off the GI entirely and using a fill light for the meantime, and the detail blending as well.

The terrain is very displaced so I will try increasing the planet displacement.  In the past I have used this to fix other issues but not these black pixel errors.

It's interesting that I don't see these errors on local renders, only when I submit it to the render farm.

Thanks for your help.

Kevin

[Oshyan]

Very strange error. Beyond what Martin said, I can't really begin to guess without seeing a TGD. Also interesting that it only happens on the render farm, is that correct? Are you using the same version as the render farm?

- Oshyan

[Seth]

strangely, i thought it was a population related problem...
are all your objects present in all your farm ?

[Henry Blewer]

I think his camera position might be inside one of the vertical outcrops. The shape is similar to the other visible displacements on the crag faces.

[Kevin Kipper]

Hi Everyone and thanks for your input.  Unfortunately, I can't upload the .tgd do to an nda but if I can recreate it in a different scene I will upload that. 

Yes, Oshyan, it's only happening on the render farm.  We have encountered different versions of Terragen running on render nodes, but I checked for that and it wasn't the case this time.

Yes, Seth, all the populations are present to the render farm. Thankfully, that hasn't been a problem for us

No, Njeneb, the camera is not inside a vertical outcrop, good call though.

Thanks again.

Kevin

[Oshyan]

Can you possibly share the TGD privately with Planetside Support? support AT planetside.co.uk. We can sign an NDA if necessary.

- Oshyan

[Kadri]

Just curious does the rocks (or whatever there is on the problematic part) have reflective surfaces , Kevin ?
I had a problem ones with this.  Together with GI this caused problems .
I could render my scene only with using a fill light setup.
Not sure if this is related with memory problems.
How much memory do your PC have and the others on the renderfarm?
Or this is directly a bug  maybe.
I have only 4 GB . But i suspect you have more
But if you use many populations etc. this could maybe affect you too.  

But as i said only guessing here