Let's take a look at the structure of a 3D print. A better understanding of the parts of a 3D print and the slicing process behind them, gives you a foundation for optimizing and customizing your print settings in the future. We'll take a close look at the print progress of this Stanford bunny, watching the physical print on the left and a 2D gcode visualization on the right. Let's start at the beginning. Many designs start with a raft. It's an open mesh of plastic that is created by your slicing software to serve as a foundation for the rest of your design.
Next, are the base or floor layers. Each has a shell or a line of plastic that traces the outside of the design. You can control the number of shells during the slicing process. This version has two. Inside, there are many parallel lines of plastic that form a solid layer. By default, the slicer will create three alternating layers to create a solid base. The thickness of these layers is called layer height. Thin layers are less prominent and produce high resolution prints, while thicker layers create low resolutions prints.
Then we move on to the standard print layers. Again, these layers have shells, but instead of a solid fill the inside contains a pattern called infill. This was printed at 10% infill, but you can choose the density from a low percentage like 5% to a much more dense 50%. There are also multiple patterns like line or hexagonal, or some decorative options as well. Near the top of the print or anywhere that the print starts to flatten out you'll see solid fill layers.
These surface layers are called roof layers. They work the same as the base layers. It leaves three alternating layers of solid lines. In a 3D print any overhangs over 45 degrees require support material. The bunny's ears just at that threshold, so we can choose to print with or without support material. When you use support material, the 3-D printer generates thin layers of plastic that support the overhanging geometry during printing and can later be broken away.
That's the basics. There are more variables if you look deeper. If you want to get into the nitty-gritty, you can change dozens of variables that interpret how the design is printed. But for now, we'll explore these customization options in more detail.
Want more? Check out Up and Running with 3D Printing for information on creating your own 3D designs to print and other 3D printing technology on the market.