The characteristics of a region described in “Swept meshing of three-dimensional solids,” Section 17.10.3, are referred to as “topological characteristics.” In some cases, all of the topological characteristics will apply to a region; however, ABAQUS/CAE will not allow the region to be swept meshed because some “geometrical characteristics” are not satisfied. The geometric characteristics that ABAQUS/CAE looks for when determining if a region is swept meshable are hard to quantify. In general, a three-dimensional region can be meshed using the swept meshing technique if it satisfies the following geometrical characteristics:

For example, Figure 17–88 shows a part with three faces on the source side. When the angle decreases between the faces that form the source side, the part no longer satisfies the geometric characteristics of a swept meshable region.

You may be able to apply virtual topology to satisfy the geometrical characteristics and to make the part swept meshable. For example, Figure 17–89 illustrates that the part becomes swept meshable when the three faces on the source side are combined using virtual topology. However, the resulting mesh is of poor quality.

In some cases ABAQUS/CAE will still allow you to create a swept mesh, even though the geometrical characteristics are not satisfied. The intention is to allow you to create a swept mesh wherever possible. However, the resulting mesh may be of poor quality, or it may be invalid. To ensure that your swept mesh is acceptable, you should use the mesh verify tool to verify its quality. For more information, see “Verifying element quality,” Section 17.17.1.