Abstract: An algorithm on 3D Modeling sketch creation of complex engineering drawing is
put forward. In the algorithm, the selected view segmentation subalgorithm is proposed. The
subalgorithm can not only combine the advantage of three existing mainstream segmentation
algorithms and segment view selectively and orderly, but also achieve the purpose of thoroughly
partitioning complicated engineering drawing by view partition four times at the most. The
improved turn-to-the-left-most rule is presented to enhance the efficiency further. Finally, the
examples indicate that the algorithm is effective, can settle some shortcomings which exist when
2D drawing is imported into the existing CAD software and improve the efficiency of 3D
geometric model.

Key words: complex engineering drawing, sketch, selected view segmentation, geometric
model