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enter image description here

In the above image, you can see that there is some slight variation of the height of each wood plank. These variations do NOT come from the wood texture itself, but from the way it was cut, i.e if a different tool had been used to cut the same plank, it would look different.= and exhibit the pattern of the tool used.

I am trying to use a perlin noise generated heightmap to approximate, to the best of my ability, this "wavy" pattern exhibited.

This image is better to see the pattern:

enter image description here

I have tried multiple strategies to modify perlin noise but I can't quite get heightmaps that look like the prior images.

My strategies so far are based around:

Stretching perlin noise along one direction, taking powers of linear combinations of the sampled noise to try to get a "bowl" shape, similar to the corner of the bottom image.

Does anyone have suggestions?

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    $\begingroup$ Doing something like Height = 1 - abs( Perlin(..) ); noise would produce bowl like shapes with ridges. Although the ridges will be sharp. $\endgroup$ – PaulHK Aug 21 at 12:23
  • $\begingroup$ Not really a rendering comment, but re "these variations do NOT come from the wood texture itself, but from the way it was cut", surely the timber would originally have been planed flat at the sawmill, and this is just natural distortions happening over time due to the timber's propeties? BTW +1 for perlin - we used it years ago to add distortions to timber grain etc $\endgroup$ – Simon F Aug 22 at 9:22
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A sine wave remapped to [0, 1] and raised to a power will give you periodic ridges: (Desmos graph)

graph of sine wave to a power

That could be a good place to start. It will make perfectly straight, even ridges; but you could then perturb the X position where the sine is evaluated using low-frequency Perlin noise, which will make the ridges bend and waver while still going mostly along the original axis. You could use noise to fluctuate the power that the sine is raised to as well, making the ridges smoother and sharper in different places.

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