# Meshing Priority

Member Posts: 11

Hi Lumerical Support team,

In your FEEM Solver Course, you refer to one example file called: soi_wg.idev.

In this example, there 3 kinds of meshing on the Silicon waveguide:

1) Mesh inside material definition of waveguide structure:

2) Mesh inside the simulation region

3) Again, Overide Mesh inside silicon waveguide:

So, As there are 3 different definitions. , how can tell which one prevails?

How can I check which one prevails?

Tali M.

• Posts: 86Ansys Employee

Hello Tali,

To better understand the mesh order, and mesh settings I would recommend the following pages

In short:

1) Mesh priority: determines what material/interfaces are used in the meshing process. This determines how the simulation is partitioned, but not actual the settings of the mesh.

2) These are global properties of the mesh, during the FEM meshing process the grid will be refined everywhere until it meets these criteria.

3) The mesh constraint allows you to change the local mesh properties. These can be used to further refine the grid in specified regions, such as near metallic interfaces where the fields will be tightly bound. If the mesh constraints are larger then the global properties 2) then those will used instead.

I hope this helps.

I would study the first link, and play around with partition and mesh command to see how these features work. You can do this by inspecting the grid.

Best,

• Posts: 33Member

Hi troberts,

How should I refer to the global mesh constraint here in the current example? If "edges per wavelength" is 2 and my wavelength is 1.55 micron, so is it quantitatively higher or lower than added mesh constraint saying "max edge length is 0.01micron?

Thanks,

Tali M.

• Posts: 86Ansys Employee

The wavelength is the wavelength in the material. This is the free space wavelength divided by n.

```lambda = lambda_0/n
```

Unless n is greater than 155 , max edge length should set mesh size

• Posts: 33Member

Great, Thanks troberts