Utilizing DICOM data is one of the best ways to ensure a 3D model accurately portrays human anatomy. The initial sacrum data shown here 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 sacral cross-sections to create a surface model.
The model generated from the DICOM data captures the form of the sacrum but had a high poly count and a rough surface that needed further refinement. Holes in the surface, detached fragments, and nonmanifold geometry also made this initial model undesirable for use in most 3D programs.
To begin cleaning up the model it was brought in to Meshmixer, a free 3D program with mesh optimization tools. Detached polygons, nonmanifold geometry, and holes in the mesh were all removed. Additionally, the jagged surface present in the initial model was smoothed. The mesh, however, remained dense at this stage.
The model was retopologized with the Instant Meshes software. This dramatically reduced the mesh density and converted all polygons to 4 sided quads. This completed the optimization of this model, making it much more manageable for use in other 3D programs and allowed for the creation of a UV map for applying textures.
The final model was taken into Cinema 4D where the fine detail was sculpted and painted. The model was rendered with Redshift.