CODEWITHSUNDEEP
terrainprocedural-generationminecraftperlin-noise
Xavier
Xavier

Reputation: 9049

How is a 3D Perlin noise function used to generate terrain?

I can wrap my head around using a 2D Perlin noise function to generate the height value, but I don't understand why a 3D Perlin noise function would be used.

In Notch's blog, he mentioned using a 3D Perlin noise function for the terrain generation on Minecraft. How would that be done and why would it be useful? If you are passing x, y, and z values, doesn't that imply you already have the height?

Upvotes: 15

Views: 15298

Answers (2)

Marcel Jackwerth
Marcel Jackwerth

Reputation: 54762

Well, Minecraft is about mines. Notch tried to solve: "How do I get holes / overhangs in my world?"

Since 2D Perlin noise generates nice/smooth looking hills, 3D Perlin noise will generate nice/smooth hills and nice holes in your 3D voxel grid.

An implementation can be found here (while that is an n-dimensional solution).

In other use cases the Z component of a 3D Perlin noise is set to the current time. This way you will get a smooth transition between different 2D Perlin noises and that can be used as groundwork for fluid textures.

Upvotes: 13

Oliver Charlesworth
Oliver Charlesworth

Reputation: 272517

The article says exactly why he used 3D noise:

I used a 2D Perlin noise heightmap... ...but the disadvantage of being rather dull. Specifically, there’s no way for this method to generate any overhangs.

So I switched the system over into a similar system based off 3D Perlin noise. Instead of sampling the “ground height”, I treated the noise value as the “density”, where anything lower than 0 would be air, and anything higher than or equal to 0 would be ground.

Upvotes: 44

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