Let’s start with a high-level overview of the process FDM printers follow, which is similar regardless of printer. You start with a digital model of your object, in STL format, either created with one of the software packages described below or downloaded from a website. You open the file in a plating and slicing program, like Makerware, Repetier host, ReplicatorG, or Pronterface. The program will show how the object sits on the build platform, and you can manipulate it to some degree (scale it up or down, rotate it for a better fit). You will then choose a number of settings for slicing, things like layer height, infill, and extrusion temperature. Once you have your settings, you will either print directly from the computer over USB or export the STL file as a gcode file and move it to the printer on an SD card. The STL will be sliced into hundreds of layers, and the 3D printer will get instructions on how to build it one layer and a time.
The other half of the 3D printing process is the software, which is of two types: one prepares your designed files for printing (slicing and plating software); the other is design software for creating the 3D object that you wish to print. We'll cover design software here.
The two filetype standards for 3D printing are .stl and .obj. Obj files are typically those used in high-end printing, and include features like color information that are superfluous for the sorts of consumer-level printing that libraries are likely to offer. For FDM and STL printing, the needed output file is a .stl format. This is the equivalent of needing a .docx file if you want to work in the most recent version of word, or a .pdf file for cross-platform document consumption. The .stl file is a very simple description, in either ascii or binary, of the external shell of a 3D object in terms of triangles. Nearly every 3D modeling software that you might use will export to .stl, it is that common a file format in 3D design.
One of the things that has really helped the 3D printing business take off is the availability of freely-sharable .stl models of just about anything you can think up. The most popular online library of 3D models is Thingiverse, a freely available resource owned by Makerbot Industries. Thingiverse allows anyone who has created a 3D model to upload it to the website and make it available for download. It’s open access 3D objects, in effect. Thingiverse is the perfect first-stop for anyone who has a 3D printer, as it will give you hundreds of things to print, from toys to tools. The downloadable files have easy to follow instructions for printing as necessary and clearly labeled intellectual property rights.
As libraries start creating and sharing objects, Thingiverse would be the logical place to store them, especially for findability by the 3D community. I’m hopeful that over time we’ll be able to find shelf brackets and more there.
I’m going to sequence this recommendation area for 3D design software from beginner to expert levels. With far more options for design software than I can cover here, this section, divided by level of expertise, is designed to give you a solid starting point. I will also point out a couple of options for the creation of STL files from photographs.
My favorite piece of software for the beginning in 3D design is a website called Tinkercad. Tinkercad is a freely-available web application for creating of 3D models by using simple shapes to build up more complicated ones. You must create an account, but the free account (at least currently) gives you unlimited models online. The free account’s only real limitation is the requirement that your creations be Creative Commons Attribution-Share Alike 3.0 license. Paid accounts get the ability to choose among all of the available Creative Commons licenses as well as the ability to control commercial distribution of their models.
Tinkercad is entirely browser-based and runs on any modern web browser, so it’s trivial to run on nearly any computer. With a well-done introductory tutorial for beginners, its method of building with simple basic shapes (cube, sphere, pyramid) allows people who are new to 3D modelling to start slowly, but still gain understanding of basic concepts. It also clearly labels the size of objects for output and allows for either solids or holes of any arbitrary shape.
Tinkercad supports importing other STL files, which means that it’s possible to download an STL from Thingiverse, import it into Tinkercad, and modify it. Though you can’t customize as robustly as with full 3D modeling software, for first steps towards creativity in the 3D realm, Tinkercad is a fantastic tool.
Similar to Tinkercad and also browser based is 3DTin. I find it less intuitive than Tinkercad, but it has some tools (camera movement, for example) that might make it a useful answer for a problem you have in 3D creation.
A step up from Tinkercad is SketchUp, software that was formerly owned by Google but sold off in 2012 to Trimble Navigation. There are two version of SketchUp available, SketchUp Make and SketchUp Pro. SketchUp Make is freely available for noncommercial use and has every capability that I can imagine a library or patron needing. SketchUp Pro is designed for professional architects and others who need very professional level controls and output.
SketchUp is ostensibly designed for architectural renderings—building interiors and exteriors, landscape design, that sort of thing. Like Tinkercad, it deals in just a few basic shapes and controls and flexible in its design uses. As a bonus, the SketchUp website has dozens of learning resources that you can use to both learn and teach with.
SketchUp doesn’t natively export to STL for 3D printing, but with an easily installed plugin you can export or import any STL file. As Google Earth and Google Maps’ primary tool for creating buildings, Sketchup is particularly handy if that’s your interest. SketchUp. It maintains a 3D warehouse of buildings and objects that can be easily opened and printed, including pretty much every famous building or sculpture in the world. Want a copy of the Taj Mahal on your desk? Not problem with SketchUp and a 3D printer. Ditto for the Empire State Building, the Arc de Triumph, or the Tennessee Aquarium. All of those are available and already modeled for your use.
Another of the free tools is Blender. Blender is an open source 3D computer graphics program that is used not only for basic 3D model creation but full animation and movie making. Of the software that I’ve mentioned, if Tinkercad is a moped, and SketchUp is a motorcycle, then Blender is a Saturn 5 rocket. It is indescribably more complex than either of the other tools to such a degree that I would really only recommend it for people who have previous experience with professional-level 3D tools.
With that caveat, it is a fully professional level tool that is capable of creating completely realized 3D photorealistic models. And it’s free. This combination means that there’s little reason not to at least play with it, or have it available if a patron wants to use it. It is worth considering whether or not you will be able to offer assistance to your patrons using Blender, because for most libraries the answer would be no. I’m not saying that’s a bad thing, only that you should be aware of the complexity of the program.
The last of the free tools I suggest taking a look at is OpenSCAD, an open source CAD editor and also a professional tool. Whereas Blender’s strength is in the artistic and creative, OpenSCAD’s strength is in the mechanical and engineering aspects of 3D modeling. If you want to model a turbine impeller or a structural support, OpenSCAD is likely your tool. Much like Blender, however, it is definitively a professional tool, requiring serious research and effort to get into.
Most of the commercial tools for 3D model creation are tied heavily to specific professions. It’s likely that if your library needs them, you’ll already know it because of local demand. Academic libraries specifically may need to pay close attention to the areas they are serving. Classes that use AutoCAD are unlikely to also teach Maya software, but either may be important to your patrons.