Manufacturing of large steel tube structures is faced with excessive welding, fit-up and rework times in tube joints, due to various types of deviation from nominal shape of the tubes. This article presents a procedure and geometry calculus for generating cutting and welding paths based on measured geometries. The procedure poses the two measured meshes as per construction specification and invokes a mesh intersection procedure to get the mesh intersection path; performs an optional smoothing; interpolates the smoothed path to a specified angular resolution; estimates the two surface normal vectors and the two surface tangents in the plane spanned by the normals at each interpolation point; calculates the cutting tool and welding tool approach directions for obtaining the specified welding groove geometry at each interpolation point; and finally stores all the data parameterized by the interpolation angle. Illustrations of results with both synthetic, representative meshes and meshes obtained from scanning of actual tubes at the shop-floor at a manufacturer are presented. The reference implementation for the developed software tool is based on Python and uses the mesh modeller from the 3D creation suite Blender as platform.

大型钢管结构的制造面临着过度的焊接，装配和返工时间，这是由于与钢管标称形状的各种偏差所致。本文介绍了一种基于测量的几何形状生成切割和焊接路径的过程和几何演算。该过程根据构造规范放置两个测量的网格，并调用网格相交过程以获取网格相交路径；执行可选的平滑处理；将平滑的路径插值到指定的角度分辨率；在每个插值点处估计法线所跨越的平面中的两个曲面法线向量和两个曲面切线；计算切削工具和焊接工具的进刀方向，以在每个插补点获得指定的焊接坡口几何形状；最后存储所有由插值角度参数化的数据。给出了合成的，代表性的网格以及通过在制造商的车间中扫描实际管而获得的网格的结果的图示。开发的软件工具的参考实现基于Python，并使用3D创建套件Blender中的网格建模器作为平台。