Draw and cut: intuitive 3D osteotomy planning on polygonal bone models

Abstract

We present a novel approach on computer-assisted 3D planning of arbitrarily shaped osteotomies on polygonal bone models. Osteotomy lines can be drawn ‘free-hand’ onto a 3D geometry, either by stroke projection or by the use of several control points, that are automatically connected in a shortest way, approximating osteotomy lines across a triangulated surface representation. Polygonal surface models are cut and retriangulated accordingly. In cases where inner structures have to be cut as well, cut surfaces are generated from closed contour lines. These surfaces again serve as an additional input for a downstream surface cut algorithm. Although focussed on cranio-maxillofacial surgery planning, the method presented herein is well suited for cutting any (manifold or non-manifold) polygonal model in a free-form manner.