If you are just learning to design without access to a 3D printer, then you can skip this step. However, since this print is so small, it is cheap, even through 3D-printing services. The ability to quickly make things for testing is one of 3D printing's greatest strengths, but it's not strictly necessary to learn how to design for them.
It's always good, especially when matching things to real-life objects, to test whether the fit is right. Some 3D printers print things smaller or larger than the file dictates. So, while the thing is small, and since 3D printers are so good at quickly testing things, test the ring you've made.
Export an STereoLithography (STL) of the ring through the Export STL option under File | Export. Name the exported file Test Ring.stl. Then, print the test ring and try it on:
It might come as a surprise that the ring doesn't fit. If printing in ABS, the plastic may have shrunk when it cooled, as that is one of the properties of ABS. Or there may be a print setting such as filament diameter that isn't correctly set. Also, internal rings created by polygons are known to be a little small sometimes. Whatever may be the reason for the ring not fitting correctly, it's a good thing it was tested while the project was still simple.
Back to Blender to make a new test ring. This time, instead of starting from scratch, reload the project and resize the existing ring. Take care to ensure that while resizing, the ring doesn't extend below the XY plane. So, to avoid this, we're going to resize the ring (and finger hole) from the Properties panel, like this:
- Start by unhiding the finger. Do this by either clicking the eye icon for the Finger object in the Outliner panel or by pressing Alt + H:
- Select the Finger object and, in the Properties panel (N), locate the Dimensions area. Change the X and Y dimensions by clicking on the number to enter Edit mode and adding a
+1after the number shown. Leave the Z dimension exactly as it is.
- Now, select the Ring object. Similarly, change the X and Y dimensions to add
1to them as well.This will make the finger hole 1 mm wider and the ring 1 mm wider as well. This way, the ring itself says the same thickness. If you don't feel as if 1 mm is enough added space, then add more to your ring. You can also make it smaller if it's too loose.
- Save (Ctrl + S) and export the model again. Print it out and test again. Keep iterating and resizing the ring until a comfortable fit is achieved. When you've got it, hide the finger object and move on.