Level surfaces helps you graph and understand 3D functions. You can not only render 3D functions, but you can export surfaces to STL files.
The rendering system uses a Marching Cubes algorithm to take points from the function and translate them to a 3D model. This works by extracting data points from the function and then creating a polygonal mesh field based on the cube's intersections.
Several algorithms for tracing 3D objects exist. These methods (sphere tracing, marching cubes, level set, dual contouring, etc) extract points to express density or orientation of points.