3d Perlin Noise?

http://answers.unity3d.com/questions/357710/c-implementing-3dperlinsimplex-noise.html http://answers.unity3d.com/questions/646054/perlin-noise-for-3d-voxel-terrain.html

http://forum.unity3d.com/threads/coherentnoise-procedural-generation-library-released.91784/

http://webstaff.itn.liu.se/~stegu/TNM022-2005/perlinnoiselinks/perlin-noise-math-faq.html

Hi,

the Youtube channel Brackeys just released a video about this topic 2 days ago. Maybe you want to check it out:

https://www.youtube.com/watch?v=vFvwyu_ZKfU

Things like caves are not explained in the video, but maybe it will help.

I was banging my head trying to get rid of the artefacts I kept seeing in the naive approach, which was found here https://www.youtube.com/watch?v=Aga0TBJkchM:

 public static float PerlinNoise3D(float x, float y, float z)
 {
     float xy = Mathf.PerlinNoise(x, y);
     float xz = Mathf.PerlinNoise(x, z);
     float yz = Mathf.PerlinNoise(y, z);
     float yx = Mathf.PerlinNoise(y, x);
     float zx = Mathf.PerlinNoise(z, x);
     float zy = Mathf.PerlinNoise(z, y);
 
     return (xy + xz + yz + yx + zx + zy) / 6;
 }

That approach may work in some cases, but for my work I kept seeing symmetrical lines throughout the data. It turns out that it was mirroring along all three axis! Terrible for a noise function to give you symmetry :)

Eventually I worked this out:

 public static float PerlinNoise3D(float x, float y, float z)
 {
     y += 1;
     z += 2;
     float xy = _perlin3DFixed(x, y);
     float xz = _perlin3DFixed(x, z);
     float yz = _perlin3DFixed(y, z);
     float yx = _perlin3DFixed(y, x);
     float zx = _perlin3DFixed(z, x);
     float zy = _perlin3DFixed(z, y);

     return xy * xz * yz * yx * zx * zy;
 }

 static float _perlin3DFixed(float a, float b)
 {
     return Mathf.Sin(Mathf.PI * Mathf.PerlinNoise(a, b));
 }

I haven't seen any artefacts in it yet.

Hope that helps you out!

EDIT: I've seen some case where there are lines again, but I'm sure someone cleverer than me an iron them out.