Often confused with marching cubes, this is more of a mathmematical concept that describes a way to define the values in 2D or 3D scalar fields based on distance to one or more points in space. They are a type of implicit surface that define blobby shapes as pure mathematical formulas rather than explicit polygons and vertices.

They can be visualized using the marching squares (2D) or marching cubes (3D) rendering algorithms. Can be used for naive fluid simulations by applying physics to the metaball center points as if they were particles. They can also be helpful in modelling soft bodies by adding elastic constraints between the center points.

A typical function chosen for metaballs is:

Where is the center of the metaball.

Articles:

• Metaballs on Wikipedia
• Metaballs (also known as: Blobs) by Ryan Geiss
• Exploring Metaballs and Isosurfaces in 2D by Stephen Whitmore

Videos:

• Coding Challenge #28: Metaballs by Daniel Shiffman (Github repo with source code for p5.js and Processing)