[phleet]

They don't inherently have to be sampled.

Just like you can define the perimeter of a circle given constants (x_0, y_0, r):

(x-x_0)^2 + (y-y_0)^2 = r^2

you can define the perimeter a metaball on a list of (x_i, y_i, r_i) as described in the post.