  A novel meshing scheme, based on regular tetra-kai-decahedron, also referred
to as truncated octahedron, cells is presented for use in spatial topology
optimization. A tetra-kai-decahedron mesh ensures face connectivity between
elements thereby eliminating singular solutions from the solution space.
Various other benefits of implementing the said mesh are also highlighted, and
the corresponding finite element is introduced. Material mask overlay strategy
or MMOS, a feature based method for topology optimization is extended for use
in 3-dimensions (MMOS-3D) via the aforementioned finite element and spheroidal
negative masks. Formulation for density computation and sensitivity analysis
for gradient based optimization is developed. Examples on traditional
structural topology optimization problems are presented with detailed
discussion on efficacy of the proposed approach.
