[Rapid prototyping.  Construction of a model in the preoperative planning of reconstructive pelvic interventions]. 
X-ray or CT images allows only a limited three-dimensional orientation in presurgical planning.  Especially for the planning of internal hemipelvectomies with custom-made endoprosthesis and for peri-acetabular osteotomies a high-grade orientation is necessary.  This orientation is improved by a 3D CT-controlled manufactured 1:1 model of the pelvis.  This enables and exact classification of defect and deformity, planning of resection planes, design of the suitable custom-made implant and simulation of the operation technique as preoperative quality control.