Papers by Keyword: Parallel Projection

Abstract: A new method of parallel projection galvanometer scanning (PPGS) is presented, as a low-cost, flexible, trans-scale solution for laser material processing on freeform surfaces. The parallel projection transformation is used for mapping three-dimensional space curves to terraced two-dimensional plane graphics that each one is suitable for traditional galvanometer scanning method. For implementation of the PPGS method, a parallel projective laser scanning system with the combination of galvanometer and telecentric lens is needed, that the laser is directed along the space curve path on freeform surface part without deviation when the x-y axis galvanometer is scanning the mapping graphic path of the parallel projection plane. In practice, the existing 3D galvanometer scan system, "3+2" and rob-scan system are alternative choices in different application situations.

Abstract: When using meshing creating method of FP (fiber placement) track, once the track point falls at some vertex point of mesh element, in the meantime the vertex point happens to be shared by several mesh elements, there needs a reasonable calculation method to select next mesh element which the FP track will pass through. Then it comes to the problem on linking of FP tracks. In order to solve it, in this paper, the author puts forward a new method, in which parallel projection theory is used, project need analytical mesh element and FP reference vector to a sound projective plane, on which the mesh element be selected and the FP track be calculated, then the FP track would be projected back to the placement surface. Program using this method realized a reasonable joint at the shared vertex point of meshing elements, which the FP direction has little change, and the mutation of track doesn’t come forth. So, the correctness of the method, which putted forward in this paper, is proved.

Abstract: It is the ideal goal for the realistic visualization to be accomplished for spatial solids with 2D presentation in digital technology. In the consistently parallel system with the viewing angle and the presenting angle, a technical term, the real presentation rate, is put forward with two indexes, clarity and tri- dimension, taken as an initial criterion of the degree to which the real presentation is reached. By using the projecting geometry, the transform matrix of two-dimensional presentation for the solids was obtained with three steps, for simple and convex body. For more intricate geometric body with concave surfaces, the furry pattern discrimination was introduced, proving that the optimum presentation is that by which the normal iso-axial viewing was adopted. An application has shown that the furry pattern discrimination method worked well, and the trend is the same as the best presentation of an object on 2D among a variety of the solutions.