A method for generating a more accurate mesh that represents a 3D printed part based on a model includes slicing the model into layers and identifying an infill-wall boundary and an exterior-interior boundary of each layer of the model. Layers of the model may be identified as critical by iterative comparison with adjacent layers. An interior voxel mesh may be constructed based on common two-dimensional reference grids imposed on the critical layers. The interior voxel mesh may be augmented to an augmented mesh and then extended to a protomesh. The protomesh may be extruded to construct the final mesh, which may be analyzed by finite element analysis. The part may be 3D printed based on the layers output by the slicing operation.