The computational domain is discretized using an appropriate meshing scheme. EM.Cube uses a non-uniform, variable, staircase (pixelated) Yee mesh with a mesh density that you can customize. A fixed-cell mesh generator is also available, where you can set constant cell dimensions along the three principal axes for the entire computational domain. The variable mesh density is specified in terms of the effective wavelength inside material media. As a result, the mesh resolution and average mesh cell size differ in regions that are filled with different types of material. EM.Cube's non-uniform mesher generates more cells in the areas that are occupied by dielectric materials, fewer cells in the free space regions and no cells inside (impenetrable) PEC regions. [[FDTD Module]]'s default "adaptive" mesh generator also refines the mesh around curved segments of lines, surface or solids to produce a far more accurate representation of your geometry. The example below illustrates a dielectric ellipsoid and a 3D view of its Yee mesh:
{| style="width: 600px" border="1" cellspacing="1" cellpadding="1"|[[Image:FDTD93.png|400px]]|[[Image:FDTD94.png|400px]]|}
Figure 1: A dielectric object and its Yee mesh in [[FDTD Module]].