An Efficient De-Overlap Algorithm for PCB Layout Patterns with Circular-Arc

This paper introduces a polygon-based method for removing overlaps of printed circuit board (PCB) pattern with circular-arc. The algorithm takes a sequence of object contours in Gerber files which consist of circular-arc polygons (i.e., polygons that have straight or circular boundary edges) in a plane as input, and outputs high quality and non-overlapping layouts. Instead of combining circular-arc polygons together, we adopt a new clipping strategy so that the bounding boxes of circular-arc polygons should remain as small as possible. The clipping algorithm is simple, robust and efficient yet it produce high quality layouts. It employs bounding boxes and spatial binning to avoid the quadratic complexity of exact intersection tests. A comparison with a brute force overlap tester are given. A number of PCB pattern experiments suggests it benefits the real-time rasterizer in decreasing running time.