Just a question.

[Tyrcrash]

On the next image I'm trying to do, I like rock outcrop on the surface of the water. But I can not use fake stones, because the shape of the heightfield does not match the height of the water. So I chose a population "rock" but obviously they are not detailed enough. So I replaced the "default shader" with a "fractal shader power" and added some displacements.
Result: the rocks seem explosed, and are completely distorted
I think it's a known problem (I met him in other situations)
Could you please give me an explanation, and, if possible, a solution?

Thanks in advance.

sorry for my bad English.

[Tangled-Universe]

The powerfractal displaces the fake stones.
What happens if you have 1m big fake stones and add a default powerfractal which applies 1m of displacement that the fake stones are likely to explode.

Here's what often works reasonably well:
Set scales of powerfractal to 10-50% of the fake stone size.
Set displacement value 50-100% of the powerfractal scale (so if feature scale of powerfractal = 0.2m, then use 0.1-0.2 metre displacement).
Set displacement offset value to 25% of displacement value. (an offset avoids flat/exploded stones often)

As you can see the fake stone size determines what scales of noise you need to apply and which amplitude/strenght of displacement.

Hope this helps.

Cheers,
Martin

[Tyrcrash]

Sorry, I think I explained myself badly: I do not have fake stones, but a population of "rock" and when to I apply the above displacements they explode ...
But thank you very much for the board, so I stands still in the dark ...

[Dune]

(an offset avoids flat/exploded stones often)

Interesting, Martin. Good to know.

I think, Tyrcrash, that for the stones in a population the same counts. But you should also up the amount of sides, maybe to 50-100 or so, to make smoother stones to start with. Also check smooth normals (I would say).

[rcallicotte]

Rocks have never worked right, have they?

[Tyrcrash]

Dune's population of rock works perfectly. I'll inspire.
Thank you very much for the advice.