virtual or real meshing
 

hi
i am meshing by gambit 2.4, i want to know that what is the differences of virtual geometry and real one?
could you tell me some advantages and disadvantages of virtual versus real geometry?

By real entities, you can use boolean tool (unite-substract-intersect). You can also easily delete entities. And split operations are less fastidious as in virtual (for example, splitting a volume with a plane is possible, but in virtual not, thus you have to split edges first, then surfaces...)
But Gambit generates automatically virtual surfaces if you are splitting or merging complex shapes in your geometry.
My advice: do all your boolean operations at the beginning, when your geometry is still real (because with virtuals, it is not possible). Also do all you splits, for your geometry decomposition with real geometry (here create some planes for that).
And finally mesh, (and clean) your geometry (here you will start to get virtual entities)