HFSS15: Six: Troubleshooting if meshing still fails

If mesh generation fails, information about the reasons for the failure is presented under Modeler>Model Analysis>Show Analysis Dialog>Last Simulation Mesh.

Again, check the box "Auto Zoom to Selection" and click on the errors in the list. This can give you hints about which parts of the model are causing difficulties.

For instance, there may be self-intersecting bodies or faces. Such errors can have a variety of causes, such as a face that is supposed to be planar, but of which the vertices don’t quite lie in the same plane. When you zoom and search you are likely to see what causes the problem.

Also, there may be face misalignments. Once you know they exist, you can inspect them and decide whether to align them under the Objects Misalignment tab.

One of the tabs of the Model Analysis window is the Surface Mesh tab. Under that tab, you can try to create surface meshes for objects and pairs of objects. Since a surface mesh on selected objects is easier to create than a volume mesh for the whole model, this can help you to identify quickly which objects are causing difficulties and why.

Also, in order to determine which objects are causing difficulties, you can exclude objects temporarily from the model. If the mesh succeeds without them, this helps to identify the reason for failure. To exclude an object temporarily, select it and uncheck "Model" in its properties window. Then try to create the mesh again.

Once you know which objects make the mesh fail, you can try to make small changes to them that don’t affect the electrical properties noticeably but help the mesh maker succeed. For example:

• Zoom in on details and consider removing details;

• Find coincident true surfaces and move one of the faces over a very short distance so the pair of faces is not coincident anymore;

• Split very complicated objects into multiple less-complicated objects;

• Delete a complicated 3D ground object and create a 2D ground through a boundary condition on the appropriate faces of a dielectric;

• Replace imported objects by objects drawn in ANSYS EM’s 3D modeling environment. For instance, some CAD tools produce cylinders that consist of two half cylinders that have a seam where they join. The fit is not always perfect.

Finally, for coincident true surfaces, set a very small value for Surface Deviation under Mesh Operations>Assign>Surface Approximation. ACIS will give them more segments, but you can compensate for that with Model Resolution. In a parametric sweep, you can experiment with settings for Surface Deviation and Model Resolution.