Glad you asked.....! A 3D cake is a normal shaped cake, like round, square, rectangle or heart, and has three dimensional art work on top. This art work is usually white modeling chocolate, but it can also be fondant, or gumpaste. This type of artwork is usually cheaper than a sculpted cake and your flavors and fillings aren't limited because there generally aren't any stability issues. Often, there is wooden skewers or even coated copper tubing within the artwork to make it secure into the cake below. It all depends on the art work being done.