Blobby objects in Flixel

In an attempt to get familiar with Flixel 2.5, I decided to create a very basic 2d metaball thing.

Metaballs are the classic blobby/soft object simulation, and were developed in the early 1980’s to model soft blobby objects that merge together smoothly – like snow or water. These types of object interactions are intractably difficult using straight-up polygon modelling.

“Proper” metaballs involve a bunch of particles, associated density functions, and a way of extracting the isosurface, such as marching cubes, marching tetrahedra or raymarching. This micro-demo does none of these things.

Nevertheless it is conceptually the same, in 2D, except using blur operations to emulate the density functions and using alpha-thresholding to emulate extracting an isosurface and re-rendering.

The code is all available on GitHub, at


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