An algorithm for extracting STL model from axisymmetric ring element mesh

Abstract

Purpose – The purpose of this paper is to use rapid prototyping (RP) technology to build physical models based on axisymmetric finite element (FE) simulation deformation results. To this end, an algorithm which extracts stereolithography (STL) model from axisymmetric ring element mesh is developed and realized by MATLAB programming. Design/methodology/approach – The algorithm first identifies boundary element edges, which compose the contour(s) of an axisymmetric ring FE mesh. Then, the identified contour edges are around the symmetry axis revolved a specific angle, at certain intervals according to certain approximate criterion, to generate new nodes to form a group of oriented triangles whose normal vectors conform to the right-handed rule. Finally, a completely closed STL model is obtained by necessary triangulation processing and rotation mapping based on original mesh. Findings – It is validated that the extracted STL model is sound and the proposed algorithm is feasible, right and characterized by linear time complexity for extracting STL model from either triangular, quadrilateral, or mixed triangular/quadrilateral axisymmetric mesh. Research limitations/implications – Color is important for expressing FE simulation results, which is not involved in STL model. Among the alternative data file formats, VRML representation is an applicable one that is complimentary to existing RP processes and suitable for color 3D printing. Based on the current work, coloring VRML model could be extracted from axisymmetric FE simulation results conveniently. Originality/value – The study of this paper provides a RP-based materialized mode to characterize axisymmetric FE simulation deformation results, which is more intuitive and visible than the computer graphics-based visualization.

Modeling of wood-like cellular materials with a geometrical data extraction algorithm

“…Stereolithographic STL models have been used as a standard geometrical model for surface representation in solid modeling and additive manufacturing. It was first introduced by 3D Systems in 1989 and has been widely used in computer aided drawing and manufacturing [Tian, 2013]. STL models represent the solid surface with triangular elements and the model files are usually in binary or ASCII formats, the difference between which is just based on the data expression method [Iványi, 2012].…”