It is actually a 2.5D field sovler. This means that you can have a stackup with many planar structures (multi-layered) as well as Via holes connecting them together.
I heard that you can define a vertical plate going through the layers (such as in a PIFA) but never tried or seen an example like this...
i agree with u , designer 1.1 and hf$$ 9.1 can cosimulate , so u can include 3d electromagnitic structures in ansoft designer , which will call HF$$ to simulate them