Set Material Override Tab
For a 3D Maxwell design, the Design Settings window includes a Set Material Override tab, which has the Enable material override check box. Normally, the modeler considers any intersection between 3D objects to be an error. But, if you check this option, the modeler allows a metal object to intersect a dielectric, and just gives a warning. Intersections between two metals or two dielectrics will still be errors.
In the mesher, the dielectrics are "subtracted" from the metals in the intersecting region. That is, the part of the dielectric that is inside the metal is removed, and if the dielectric is completely inside, the whole object disappears.
The purpose of this feature is to allow you to avoid doing explicit subtraction in the modeler. One example application is a via that passes through many dielectric layers – with the option turned on, the via does not have to be subtracted from the layers.