Yes, you got the idea of having it 3D printed rotated on a flat back for example and thus going without the need to use support materials. When you are 3D printing on your home 3D printer you usually do not go for solid insides of the object as it is taking up more material and time to print and is rarely beneficial. Instead you use about 10-20% of infill and the 3D printing software uses a hexagonal or round pattern to fill the inside, so you get enough strength without having it 100% solid.