To review what a metaball is, and how to render them and to describe a new optimization I ve made for rendering metaballs. For complex scenes, it can render hundreds of times faster, though I m certain others have discovered this trick as well. It does very slightly change the characteristic shape of the blobs, but there is no loss in image quality whatsoever. (I actually developed all this about two years ago, but just now felt like writing it all down, and had the time!)