[[Image:wire_pic1.png|thumb|350px|EM.Libera's Navigation Tree.]]
All the objects in your project workspace are organized into object groups based on their material composition and geometry type in the "Physical Structure" section of the navigation tree. In EM.Libera, you can create three different types of objects (click on each type to learn more about it):
* {| class="wikitable"|-! scope="col"| Material Type! scope="col"| Applications! scope="col"| Geometric Object Types Allowed|-| style="width:150px;" | '''[[Defining_Materials_in_EMGlossary of EM.Cube's Materials & Physical Object Types#Perfect_Electric_Conductors_.26_Metal_Traces Perfect Electric Conductor (PEC) | Perfect Electric Conductor (PEC) Objects]]'''* | style="width:300px;" | Modeling perfect metals| style="width:250px;" | Solid, surface and curve objects|-| style="width:150px;" | '''[[Defining_Materials_in_EMGlossary of EM.Cube's Materials & Physical Object Types#Thin_Wires Thin Wire | Thin WiresWire]]'''* | style="width:300px;" | Modeling wire radiators| style="width:250px;" | Curve objects|-| style="width:150px;" | '''[[Defining_Materials_in_EMGlossary of EM.Cube's Materials & Physical Object Types#Defining_Dielectric_Materials Dielectric Material | Dielectric ObjectsMaterial]]'''| style="width:300px;" | Modeling any homogeneous material| style="width:250px;" | Solid objects|}Â Click on each category to learn more details about it in the [[Glossary of EM.Cube's Materials & Physical Object Types]].
Both of EM.Libera's two simulation engines, Wire MoM and Surface MoM, can handle metallic structures. You define wires under '''Thin Wire''' groups and surface and volumetric metal objects under '''PEC Objects'''. In other words, you can draw lines, polylines and other curve objects as thin wires, which have a radius parameters expressed in project units. All types of solid and surface CAD objects can be drawn in a PEC group. Only solid CAD objects can be drawn under '''Dielectric Objects'''.