When animated, metaballs take on a strange fluidity. Use the left mouse button to place metaballs. The Display menu allows you to select what is being displayed. You can display the metaballs as just wireframe spheres, the shaded isosurface, or the polygonal mesh after the marching pyramids. The Features menu lets you toggle environment mapping, and animation of the metaballs.
Environment mapping is turned on by default.
Animation is turned off by default. The Video Recording menu allows you to record videos in a compressed SGI format. The marching cubes algorithm is a way to render a 3d solid data set by producing a polygonal mesh from it and rendering that. It works by splitting the 3d space into a grid of cubes, traversing the the space cube by cube, and producing polygons in those cubes which intersect the iso-surface of the dataset. Each vertex of the cube can either be inside or outside of the solid.