With the exception of the Made in Space printer on the International Space Station, FFF/FDM printers are subject to gravity. Higher portions of your model will need a foundation or support from the lower ones. As a design consideration, you'll want to be conscious of the slopes in your piece, the overhangs. The angle of those overhangs impact how far a layer extends over the previous layer one. If a layer extends out too far, the filament could droop or curl up, causing imperfections, or worse, a failed print.
For most FFF/FDM desktop printers, the rule of thumb is 45 degree overhangs. If you keep your slopes and curves to 45 degrees or less, each layer will have a good foundation with the layer underneath. When you look at larger ...
