Rapid bridging method of polygonal area containing plurality of holes

Abstract

The invention discloses a rapid bridging method of a polygonal area containing plurality of holes. The method comprises the following steps: inputting an outer-contour polygon and several inner-contour polygons; copying and storing coordinate of vertexes of each polygon and simultaneously recording serial number of each vertex on corresponding polygon and serial number of the polygon in the polygon array so as to obtain a planar point cloud; carrying out Delaunay triangularization on the point cloud to obtain a plane triangle array; deleting useless triangles in the plane triangle array; establishing an initial bridge inside each triangle remaining to connect two corresponding polygons so as to obtain an initial bridge array; finding out several useful bridges in the array and using the bridges to bridge all inner-contour polygons to the outer-contour polygon; and finally outputting an unified polygon containing the inner-contour polygons and the outer-contour polygon. According to the invention, a plurality of inner-contour polygons on a plane domain can be bridged to an outer-contour polygon within approximate linear time. Rough-machining path generation efficiency is raised.

Description

technical field [0001] The invention relates to the technical field of three-dimensional printing, in particular to a method for quickly bridging polygonal regions containing multiple holes. Background technique [0002] In the rough machining path planning of the layer cutting method, a plane with a variable layer height is used to cut parts and blank models first, and several processing areas on the layer plane are obtained. These processing areas are bounded by a series of polygon nests. Take one of the processing areas as an example. This area is surrounded by a polygon representing the outer contour and zero or more polygons representing the inner contour. The direction of the polygon of the outer contour is generally expressed as counterclockwise, and the direction of the polygon of the inner contour is generally expressed as clockwise. hour hand. In the processing area, the commonly used tool path forms are parallel and circular. The parallel path generation algori...

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Problems solved by technology

Wong TN, Wong KW studied the automatic bridging method of the inner contour in the area in their article, but the time complexity of this method is of the order of squares. When the number of inner contours in the area is large or there are many points on the inner contour, It takes a lot of time to bridge the inner contour with this method (see Wong TN, Wong KW, NC toolpath generation for arbitrary pockets with Islands, The International Journal of Advanced Manufacturing Technology, 1996, 12(3): 174-179)

[0006] To sum up, for the bridging problem of polygonal processing areas containing multiple holes, the existing technology is not complete enough, and it still stays at the level of manual bridging or automatic bridging with quadratic time complexity

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