Unwanted Termite Mounds

[PabloMack]

I am using a "fractal terrain" to add interesting relief to my terrain. But it is generating these strange high frequency "Termite Mounds" that shouldn't be there. I am presuming that this is caused by some low-end frequency generator but I haven't been able to get rid of it. It is on top of a heightfield. If I disable the heightfield it isn't there any more and if I disable the fractal terrain node (leaving the height field enabled) it isn't there any more. It is apparently caused by an interaction of the two. Does anyone have experience with these things?

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[Dune]

Does it smooth the heightfield first? That might be the thing....

[PabloMack]

Does it smooth the heightfield first? That might be the thing....

I turned off "flatten surface first" because it was putting the heightfield in the middle of a berm like refineries do large tanks fillied with gasoline ("petrol" for you European folks) to contain spills. I know I have to try different seed values for the fractal terain because some have a problem and some don't.

[Oshyan]

I wonder if there might be very small, very tall (spiky) features in the heightfield that the subsequent displacement is "amplifying"...

- Oshyan

[PabloMack]

It was my impression that the fractal terrain just added to the heightfield and that it didn't use its data to compute any of its own displacements. I decided later that the mesa was too large for my purpose and I scaled it down by a factor of 2.5. After that the termite mounds mysteriously went away so they are no longer a problem. The heightfield grid points are at one meter spacing so I don't see how they could contain noise high frequecy enough to account for them. They are certainly not visible on the object model that I generated the heightfield from. There is another potential place for their source and that is the process of converting the mesh model into a heightfield. But because of the one meter spacing in the heightfield it is still a mystery.