fractal artefacts?

[Dune]

I was experimenting with (amongst others) a glacier, when I noticed that some rocks behaved strangely. The overall small displacement seems to be stretched or warped, or whatever you call it (encircled). There's almost always some rocks that flatten in a strange way. Does anyone know how to avoid this? You don't always see it until a large render is completed.

---Dune

[Henry Blewer]

I have had this happen. I just call them puddles and throw a disk with a water shader over it. Mine occur on the horizontal parts of the rocks.
This happens when I use a lot of noise in the tweak noise tab.

[inkydigit]

looks like becoming an excellent render btw, sorry I cant help!

[Tangled-Universe]

Cool render!
You use fake stones for the rocks I see, did you disable "blend as stone density"?

[Dune]

Yes, I learned well from this forum  Perhaps if I throw another fractal over the first (or merge them) it would texture the flat areas as well.

[Tangled-Universe]

I thought so too, but perhaps you missed it somehow, so therefore I tried.
Disabling the blend as stone density fixes it mostly, but still you can get odd shapes. Perhaps a new seed might help, but it could also make it worse, difficult to say.
I don't know (yet) how useful the displacement tolerance setting in the planet-node is for this. None to very little is explained about this so far.
Perhaps changing it with tiny amounts could help, but it's really a wild uneducated guess.

Martin

[RArcher]

The only help i've found with the displacement tolerance in the planet node is when parts of the image are not rendering at all or getting cut off like this:  http://forums.planetside.co.uk/index.php?topic=5553.msg58325#msg58325

My guess for your problem would be as Martin suggested playing with the seed until you get a mostly clean set of stones.