Curved surface slicing algorithm of additive manufacturing digital model based on the combination of inner and outer bounding box and projection method

Abstract

To address the issue of low intersection efficiency in curved surface slicing of an STL model in additive manufacturing, this study proposes a novel curved surface slicing algorithm that integrates inner and outer bounding boxes with a projection-based approach. The proposed methodology is outlined as follows: Firstly, during the intersection process between the curved surface layer and the model, oriented bounding boxes (OBBs) are constructed for both the curved surface layer and the model to identify the intersecting regions, and the triangles located within the intersecting regions are selected. Secondly, the inner bounding boxes are constructed within the curved surface layer, the triangles located within the intersecting regions of the model and the inner bounding boxes are then projected onto the XOZ and YOZ planes, and the triangles of the model that do not intersect with the curved surface layer are effectively removed by Boolean operations. Finally, after two rounds of screening, an axis-aligned bounding box (AABB) is constructed for both the remaining triangles of the model and the triangles of the curved surface layer within the intersecting region, the intersection calculations are then performed on the triangles that are likely to intersect. The algorithm is applied to the STL model of impeller blades, and the results demonstrate significant improvements in computational efficiency. Specifically, the time complexity of the proposed algorithm is approximately 37 % of that of the brute-force intersection algorithm and 77 % of the hierarchical bounding box algorithm. Furthermore, the running time is reduced to 18.6 % of that of the brute-force intersection algorithm and 47.6 % of the hierarchical bounding box algorithm. These results substantiate the feasibility and efficiency of the proposed algorithm in enhancing intersection calculations in additive manufacturing processes.