1. A method for producing a three-dimensional structure from a digital model, comprising: determining a plurality of two-dimensional layers in response to the digital model; rendering an image corresponding to a set of the layers on a plurality of sheets of at least partially transparent material; and assembling the plurality of sheets of material together to produce a three-dimensional structure corresponding to the digital model, wherein the step of determining a plurality of two-dimensional layers comprises, for each layer in the set of layers: determining vectors corresponding to pixels of the layer; determining rays having an origin at the pixels and a direction parallel to the vectors; determining intersections of the rays with a surface of the digital model; and determining colors of the surface of the digital model at the intersections.