Very little 3D stuff on the web involves less than a couple of megabytes of JavaScript. The “hello world” of Three.js results in a bundle size of almost half a megabyte (484 kB, 122 kB gzipped), and it used to be a lot bigger—it’s been a hard slog for them to get it even that low. You just can’t seem to do much with WebGL without spending a few hundred kilobytes of code. The “hello world” of VoxCSS is just under 40 kB (12 kB gzipped). No idea if any effort has gone into shrinking it.