This quality control criterion consists in calculation of the maximal length of edges and diagonals of 3D mesh elements (tetrahedrons, pyramids, etc). For polyhedra the value is always zero.
To apply the Element Diameter 3D quality criterion to your mesh:
Display your mesh in the viewer.
Choose Controls > Volume Controls > Element Diameter 3D or click "Element Diameter 3D" button in the toolbar.
Your mesh will be displayed in the viewer with its elements colored according to the applied mesh quality control criterion:
See Also a sample TUI Script of a Element Diameter 3D quality control operation.