a metaball is a surface defined by summed influence fields. each point generates an invisible force that weakens with distance. where multiple fields overlap strongly enough, surfaces merge organically.
close to center = strong field
far from center = weak field
sum all circles at any point
where sum ≥ 1.0 = visible surface
charge — negative = repulsion fieldradii — larger circles dominatefalloff — exponential or linear decaybodies — multiple autonomous circles3d — metaspheres via marching cubes