Computer-implemented systems and methods for preparing a virtual three-dimensional (3D) object for 3D printing are provided. A hollowed-out representation of an input model is generated. The input model defines a solid virtual 3D object, and the hollowed-out representation comprises a shell and an internal volume that is a void. The internal volume is meshed to generate a polygonal mesh representation of the internal volume. A lattice microstructure corresponding to the polygonal mesh representation is generated by (i) replacing each edge of the polygonal mesh representation with a solid part, and (ii) uniting the solid parts to form the lattice microstructure. A lightweight representation of the input model is generated, where the lightweight representation comprises the shell and the lattice microstructure.