A method of determining containment relation and orientation for complex contours*

Abstract

In 3D printing, the containment relation and orientation of complex contours are key issues for slicing algorithm. An effective method is proposed to determine the inner and outer orientational contours based on kernel points. At the specified height crosss-section of the model, kernel points are calculated according to the polygon enclosed by the intersection points where cross-section intersects with the model. Kernel line is obtained by any two kernel points. The intersection points that the kernel line intersects with contours are used to determine the containment relation. The containment relation is related with orientation of the contour ring. According to the line segment between any two adjacent points and the kernel point, the orientation of the contour is quickly determined by calculating the intersection points where the line segment and the contour intersects. Case study shows that the method proposed can effectively determine the containment relation and orientation for complex contours with a significantly reduced time complexity.