A computing method for accurate slice contours based on an STL model

The STL model has become a standard in rapid prototyping (RP) technology, but slice errors are high because of tessellation. To improve the precision of slice contours, a novel slicing method is presented to compute accurate contour curves based on an STL model. First, the normal vector of a triangle facet to be sliced is calculated. An interpolation curve between two vertices is constructed in a normal section to approximate the original curve in the normal section in terms of the position of the two vertices and the tangent vector at the two vertices. The exact points of the slice contour are obtained by calculating the intersection points between the interpolation curve and the slice plane. Finally, accurate smooth contours are achieved by fitting the intersection points with a cubic B-spline curve. The experimental results indicate that the presented slicing method improves the precision of cross contours.