Abstract: In order to solve the problem of curve recognition and extraction for laser 3D contour projection,a method based on OpenCASCADE (OCC) platform is proposed. This method uses OCC,an open source 3D geometry engine,to read the digital model of the projected part,combine the relevant geometric and topological data structures,and identify the type of sectional curve based on local geometric properties. Finally,the contour coordinate data is written into the PLY file by sampling methods such as equal arc length and segmentation. Based on the above curve recognition and extraction methods,a 3D contour curve recognition and extraction system is developed. The system can be applied to the projection indication in the fields of machinery manufacturing and composite layering,which provides effective support for the realization of digital manufacturing.

Key words: edge contour data, projection file, cross-section characteristics, OpenCASCADE platform