How to create this design or what the effect is called?

[benmacx]

I have recently been looking at designs like this and I want to recreate the image but can't find out what it is called or work out how to do it as good as this. Can somebody help?

 

[Paul Murray]

I would guess they were procedurally generated through 3D via some form of code as they remind me of fractals. You could possibly do it manually using some form or extrude/turbulence modifier on a 3D surface but it looks too random to be done by hand. There's a lot of talented people out there though, so you never know.