[[File:PO24.png]]
Figure 1: Forcing mesh cells to be single-sided in a PO simulation.
'''As a general rule, EM.Cube's PO mesh generator merges all the objects that belong to the same surface group using the Boolean Union operation.''' As a result, overlapping objects are transformed into a single consolidated object. This is particularly important for generating a contiguous and consistent mesh in the transition and junction areas between connected objects. In general, objects of the same CAD category can be "unioned". For example, surface objects can be merged together, and so can solid objects. However, a surface object and a solid in general do not merge. Objects that belong to different groups on the Navigation Tree are not merged during mesh generation even if they are all of PEC type and physically overlap.
[[File:PO25.png|400px]] [[File:PO26.png|400px]]
Figure 2: Geometry and PO mesh of an overlapping sphere and ellipsoid.
=== Mesh Density & Local Mesh Control ===