“Meshing multiple three-dimensional solid regions,” Section 17.12.1, describes how the default meshing techniques applied to adjacent regions of a three-dimensional solid part or part instance may not allow you to generate a mesh that is compatible across the regions. In contrast, adjacent regions of a two- or three-dimensional shell part or part instance are always compatible.

Figure 17–96 illustrates a three-dimensional shell part instance with adjacent regions that ABAQUS/CAE can mesh using the free, swept, and structured meshing techniques.