In EM.Ferma, materials and sources are all listed under the "Physical Structure" section of the navigation tree. In other words, there is no separate "Sources" section. For example, you can define default zero-potential perfect electric conductors (PEC) in your project to model metal objects. You can also define fixed-potential PEC objects with a nonzero voltage, which can effectively act as a voltage source for your boundary value problem. In this case, you will solve the Lapalce equation subject to the specified nonzero potential boundary values. Both types of PEC objects are defined from the same PEC node of the navigation tree by assigning different voltage values. Charge and current sources are defined as CAD objects, and you have to draw them in the project workspace just like other material objects.
=== Variety of Grouping Objects by Material and or Source Objects Type ===
Your physical structure in EM.Ferma is typically made up of some kind of source either in the free space or in the presence of one or more material objects. EM.Ferma's electrostatic and magnetostatic simulation engines then discretize these source and material objects and solve the Laplace or Poisson equations to find the electric or magnetic fields everywhere in the computational domain.
Â
All the CAD objects in the project workspace are organized together into object groups which share the same properties including color and electric or magnetic [[parameters]]. Once a new object group node has been created on the navigation tree, it becomes the "Active" object group of the project workspace, which is always listed in bold letters. When you draw a new CAD object such as a Box or a Sphere, it is inserted under the currently active surface type. There is only one object group that is active at any time. Any group can be made active by right clicking on its name in the navigation tree and selecting the '''Activate''' item of the contextual menu. It is recommended that you first create object groups, and then draw new objects under the active surface group. However, if you start a new EM.Ferma project from scratch, and start drawing a new object without having previously defined any object groups, a new default PEC object group is created and added to the navigation tree to hold your new CAD object.
Â
[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Defining_Materials_in_EM.Cube#Defining_a_New_Material_Group | Defining a New Object Group]]'''.
Â
[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Defining_Materials_in_EM.Cube#Moving_Objects_among_Material_Groups | Moving Objects among Different Groups]]'''.
Â
=== Variety of Material Objects ===
EM.Ferma offers the following types of material objects for construction of your physical structure:
{{Note| Excluding surface and curve CAD objects, you can define any solid CAD object as a dielectric or magnetic material object.}}
Â
=== Variety of Source Objects ===
EM.Ferma also offers the following types of source objects for excitation of your physical structure:
* Volume Currents
* Permanent Magnets
Â
All the CAD objects in the project workspace are organized together into object groups which share the same properties including color and electric or magnetic [[parameters]]. Once a new object group node has been created on the navigation tree, it becomes the "Active" object group of the project workspace, which is always listed in bold letters. When you draw a new CAD object such as a Box or a Sphere, it is inserted under the currently active surface type. There is only one object group that is active at any time. Any group can be made active by right clicking on its name in the navigation tree and selecting the '''Activate''' item of the contextual menu. It is recommended that you first create object groups, and then draw new objects under the active surface group. However, if you start a new EM.Ferma project from scratch, and start drawing a new object without having previously defined any object groups, a new default PEC object group is created and added to the navigation tree to hold your new CAD object.
Â
[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Defining_Materials_in_EM.Cube#Defining_a_New_Material_Group | Defining a New Object Group]]'''.
Â
[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Defining_Materials_in_EM.Cube#Moving_Objects_among_Material_Groups | Moving Objects among Different Groups]]'''.
=== Fixed-Potential PEC Objects===
Under the static condition, every point on a PEC object has the same electric potential. By default, this is a zero potential, meaning the PEC object is "grounded". You In EM.Ferma, a PEC group has a ''Fixed Potential''' property, which is expressed in Volts and has a zero default value. If you define a new PEC group and keep its default zero voltage, the objects belonging to that group will simply act as metal objects of your physical structure. However, you can define a nonzero voltage value for a PEC group. You can do in the property dialog of the PEC group, which you can access by right-clicking on the group's name in the navigation tree and selecting '''Properties...''' from the contextual menu. In that the caseof a nonzero voltage, all the PEC objects belonging to that group are effectively turned turn into voltage sources. For example, two parallel PEC plates, one with a zero potential and the other with a nonzero potential represent a simple air-filled capacitor. Â To add a new Fixed-Potential PEC group to a project, right-click on "Fixed-Potential PEC Objects" on Note that the Navigation Tree, and select "Insert New PEC..." From the PEC dialog, you voltage value can change the default red color and set a value for the "Voltage" in Voltsbe positive or negative.
<table>
<tr>
<td> [[Image:Static1.png|thumb|270px330px| EM.Ferma's PEC dialog.]] </td><td> [[Image:Static2.png|thumb|270px330px| EM.Ferma's Dielectric/Magnetic Material dialog.]] </td>
</tr>
</table>