{{Note|Under dielectric material groups, you cannot draw surface or curve CAD objects.}}
<table><tr><td> [[Image:wire_pic2Info_icon.png|thumb|350px|EM.Libera's PEC dialog.40px]] </td><td> Click here to learn more about '''[[Image:wire_pic3Defining_Materials_in_EM.pngCube#Defining_a_New_Material_Group |thumb|350px|EM.LiberaDefining a New Material Group]]'''s Dielectric dialog.]] </td></tr></table>
=== Moving Objects Between Groups & Modules === Once a new surface node has been created on the navigation tree, it becomes the "Active" surface 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 surface group that is active at any time. Any surface type 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 surface groups, and then draw new objects under the active surface group. However, if you start a new [[EM.Illumina]] project from scratch, and start drawing a new object without having previously defined any surface groups, a new default PEC surface group is created and added to the navigation tree to hold your new CAD object.
By default, the last object group that was defined n the navigation tree is active[[Image:Info_icon. The current active group is always listed in bold letters in the navigation tree. All the new objects are inserted under the current active group. A group can be activated by right-clicking on its entry in the navigation tree and then selecting the png|40px]] Click here to learn more about '''Active''' item of the contextual menu[[Defining_Materials_in_EM. You can move one or more selected objects to any desired PEC group. Right click on the highlighted selection and select Cube#Moving_Objects_among_Material_Groups | Moving Objects among Material Groups]]'''Move To > MoM3D >''' from the contextual menu. This opens another sub-menu with a list of all the available PEC groups already defined in the  {{Note|In [[PO ModuleEM.Cube]]. Select the desired PEC group, and all the selected objects will move to that group. The objects you can be selected either in the project workspaceimport external CAD models (such as STEP, or their names can be selected from the Navigation Tree. In the latter caseIGES, make sure that you hold the keyboard's '''Shift Key''' or '''Ctrl Key''' down while selecting a PEC group's name from the contextual menuSTL models, etc. In a similar way) only to [[CubeCAD]]. From [[CubeCAD]], you can then move one or more the imported objects from a Physical Optics PEC group to [[EM.Cube|EMLibera.CUBE]]'s other modules. In this case, the sub-}} [[menusImage:Info_icon.png|40px]] Click here for a general discussion of the''' Move To >''' item of the contextual menu will indicate all the [[Defining Materials in EM.Cube|EM.CUBE]] modules that have valid groups for transfer of the select objects'''.
== 3D Mesh Generation ==