The color of a region in the Mesh module indicates the meshing technique currently assigned to that region. The color coding is as follows:
Structured meshing technique: green
Free meshing technique: pink
Swept meshing technique: yellow
Unmeshable: orange
In many cases ABAQUS/CAE can use more than one technique to mesh a region; in these cases you can either accept the default technique, or you can use the Mesh Controls dialog box to select an alternative technique. In addition, you can change which meshing techniques are valid for a region by adding partitions to the region or by assigning a different element shape to the region. For example, if you change the element shape assignment of an unmeshable three-dimensional part instance from hexahedra to tetrahedra, the part instance becomes meshable using the free-meshing technique. For more information, see Why partition in the Mesh module?, Section 17.6.3.
For detailed information on controlling the mesh technique and element shape assigned to a region, see the following sections: