A COMPARATIVE-STUDY ON DIFFERENT METHODS OF AUTOMATIC MESH GENERATIONOF HUMAN FEMURS

The aim of this study was to evaluate comparatively five methods for a utomating mesh generation (AMG) when used to mesh a human femur. The f ive AMG methods considered were: mapped mesh, which provides hexahedra l elements through a direct mapping of the element onto the geometry; tetra mesh, which generates tetrahedral elements from a solid model of the object geometry; voxel mesh which builds cubic 8-node elements di rectly from CT images; and hexa mesh that automatically generated hexa hedral elements from a surface definition of the femur geometry. The v arious methods were tested against two reference models: a simplified geometric model and a proximal femur model. The first model was useful to assess the inherent accuracy of the meshes created by the AMG meth ods, since an analytical solution was available for the elastic proble m of the simplified geometric model. The femur model was used to test the AMG methods in a more realistic condition. The femoral geometry wa s derived from a reference model (the ''standardized femur'') and the finite element analyses predictions were compared to experimental meas urements. All methods were evaluated in terms of human and computer ef fort needed to carry out the complete analysis, and in terms of accura cy. The comparison demonstrated that each tested method deserves atten tion and may be the best for specific situations. The mapped AMG metho d requires a significant human effort but is very accurate and it allo ws a tight control of the mesh structure. The tetra AMG method require s a solid model of the object to be analysed but is widely available a nd accurate. The hexa AMG method requires a significant computer effor t but can also be used on polygonal models and is very accurate. The v oxel AMG method requires a huge number of elements to reach an accurac y comparable to that of the other methods, but it does not require any pre-processing of the CT dataset to extract the geometry and in some cases may be the only viable solution. (C) 1998 IPEM. Published by Els evier Science Ltd. All rights reserved.