Abstract: To improve the accuracy of the ship geometric properties calculation and the real-performance of the program, a method based on STL triangular mesh model was proposed to calculate the ship geometric properties. SH polygon clipping algorithm in computer graphics was used to calculate the intersection of ship and water plane. By using of coordinates systems affine transformation, 3D water plane was changed to 2D plane to extract the profile contour. Because the waterlines are monotone polygon, Mass center insertion method was proposed to finish polygon triangulation, computing speed was improved. Bulk carrier "Taihang 128" was taken as an example, comparing the calculated results with the data given in loading manual, there is almost no accuracy loss. The results indicate that the proposed method has high accuracy and good real-time performance and has a certain practical application value.

Key words: marine engineering, vessel's geometric properties, triangular mesh model, SH clipping algorithm, section contour, triangulation