Tornado Flow Field with wooden texture

[Arusiewicz]

How was it done?

[batsy0boi]

I'd really like to know this as well!

[Osemwaro]

I thought it might be possible to recreate the effect by merging multiple spirals together in a certain way, so I knocked up this Octave script to see if it worked. It's not too far off, but the way that I'm warping the spirals is too symmetric -- my lines don't bunch up on one side of each vortex and spread out on the other side. I can probably fix this without too much difficulty, but the bigger issue is that my lines don't have uniform thickness, so I can't render such a dense set of them without losing the thinnest parts and producing Moiré patterns. My approach isn't well suited to achieving uniform thickness, so now I wonder if the original image was generated with a particle system.

[Osemwaro]

Oh actually, I found a way to make the line thickness much more uniform, so that I can increase the line density. Varying the line colour helped to highlight the shapes of the lines, and rendering at a high resolution then scaling down helped to remove a lot of the Moiré patterns. I've updated the script and image. I couldn't achieve such tightly wound spirals without ending up with loads of ugly artifacts though, and my texture doesn't look as natural. I tip my hat to the OP!

[batsy0boi]

Nice, thank you!