The invention relates to an operation planning system for the reconstruction of missing or damaged bone parts, having a device for importing 3D image data relating to at least one osseous donor region, means for processing the 3D image data into structured data, such that osseous portions can be distinguished from soft tissue portions and/or vascular systems, means for importing 3D target data relating to a missing or damaged bone part, means for receiving one or more 3D target curves in relation to the 3D target data and/or the 3D data of the donor region, means for segmenting the osseous portions of the osseous donor region, means for joining the segments into a reconstruction, wherein the segmenting of the osseous portions is adapted to 3D target curves on 3D surfaces of the 3D target data.
