Scroll down to see my process.
The initial sacrum data was isolated using the region of interest (ROI) feature in Horos, shown in green. The data was obtained from the Osirix DICOM file labeled "Mecanix, Vasculaire Angio_Aorte." The program then used the isolated regions of the scacral cross sections to create the initial 3d model.
After adjusting the model tolerances in Horos, the initial models were generated as shown. The overall form of the sacrum was achieved but the dense mesh, and uneven surface required further refinement. Additionally, the Horos generated model included holes, floating fragments and cancellous bone on the interior of the model that needed to be removed.
The mesh was then taken into Meshmixer, a free Autodesk supported program, to fill the holes, remove the interior surfaces, fix nonmanifold geometry, and decrease the irregularity on the surface of the model.
To decrease the density of the mesh and convert the polygons to quads, the model was brought into the program, Instant Meshes. This allowed the model to be UV mapped and textured.
The final model was lit, textured, and painted in Cinema 4D and rendered using Cinema 4D's Physical Renderer.