Truth is, there's not much practical point to 3D printing if it can't be used to make real-life objects that conform to real life. Making measurements and applying those measurements to virtual objects is mandatory in 3D design. A ruler will do the trick in some cases, but more complex objects will require more robust tools. Calipers are a designer's best friend most of the time. Tracing the object onto graph paper can help transfer a complex shape into the computer, where it can be recreated. Finally, for the professional, a 3D scanner can quickly transfer a complex shape, but at considerable cost. The more options you have available, the better designer you will be.

In the next chapter, we'll use measurements to create a 3D model that will match a real-life object when we're done.