The region contains some small edges or the seed density is too coarse. You can use the Virtual Topology toolset to merge small edges. Alternatively, if you save the region that failed to mesh in a set, you can apply local seeds of a finer density to the saved set.

Bad geometry refers to small edges or faces or to part instances that are imprecise. You can use the Query toolset to check the geometry. For more information, see “Using the geometry diagnostic tools in the Part module,” Section 11.28.

When you are creating a free mesh with tetrahedral elements, ABAQUS/CAE first creates a triangular mesh on the external faces of the region and then uses those triangles as faces of the exterior tetrahedral elements. You can choose to preview the triangular mesh on the faces and decide if it is acceptable before continuing with the time-consuming process of generating tetrahedral elements through the interior of the region. For more information, see “What is a tetrahedral preview mesh?,” Section 17.9.4.

In some cases ABAQUS/CAE cannot complete the conversion from triangles to tetrahedra and highlights the nodes on the boundary mesh that cannot be inserted into the tetrahedral mesh. The highlighted nodes serve as indicators of regions that require attention, and you can try the following:

You can generate a gasket reinforcement mesh only on a region that is a gasket mesh.