In EM.Cube’s [[FDTD Module]], objects are grouped together and organized by material under the “Physical Structure” node of the Naviation Tree. Since you selected no material for your line object, the first drawn object is automatically assigned a <i>PEC_1</i> material group. The default perfect electric conductor (PEC) group is set as the active material. When a material group is set as active, its name appears in bold letters, and all subsequently drawn objects will be placed under that material node. Any material group can be set as the active material by right-clicking on its name in the Navigation Tree and selecting <b>Activate</b> from the contextual menu.
==Computational Domain & Boundary Conditions==
The boundary Conditions at the six faces of the computational domain can be set by selecting the menu item <b>Simulate &rarr Computational Domain &rarr Boundary Conditions…</b> or by right clicking on the “Boundary Conditions” item in the “Computational Domain” section of the Navigation Tree. By default, EM.Cube’s [[FDTD Module]] assumes an open-boundary physical structure. All the six boundaries default to <b>PML</b>, or Perfectly Matched Layer, which you are going to maintain for this tutorial lesson. But the dropdown lists allow you to also choose <b>PEC</b>, or a Perfect Electric Conducting boundary, or <b>PMC</b>, a Perfect Magnetic Conducting boundary.
==Source Definition==