Mechanical Engineering - 3D Printing
Starting with an existing model
The easiest way to learn to design models for 3D printing is perhaps to modify an existing model. There are several free or paid models available.
- ThingiverseA very large number of free models.
- NASA 3D ResourcesCollection combining 3D models, textures, and images from NASA.
- GrabCADModels shared by a community of over 10 million engineers.
- NIH 3D Print ExchangeModels compatible with 3D printers and all tools for designing and sharing 3D models in the field of biomedical science, including molecules and proteins.
- 3D WarehouseMillions of free models created in SketchUp (not all are convenient for 3D printing).
- YouMagineThousands of open-source designs.
Designing your own model
Once you have mastered the basics of modeling and have become familiar with the software, you can start exploring how to create your own model. You are only limited by your imagination…and the specifications of the machine, material, and printing technique you choose!
This head is made up of hundreds of triangles
The STL format
The STL file format (for STereoLithography) has become the norm in 3D printing. Most machines and modeling software support it.
Such files contain, most often in plain text, the list of triangles (facets) that make up the object with their 3D coordinates (X, Y, Z axes). So, to design a cube, you need 12 triangles as demonstrated in the example below:
Click to scroll through the STL format code
solid MYSOLID
facet normal 0.0 0.0 -1.0
outer loop
vertex 0.0 0.0 0.0
vertex 1.0 1.0 0.0
vertex 1.0 0.0 0.0
endloop
endfacet
facet normal 0.0 0.0 -1.0
outer loop
vertex 0.0 0.0 0.0
vertex 0.0 1.0 0.0
vertex 1.0 1.0 0.0
endloop
endfacet
facet normal -1.0 0.0 0.0
outer loop
vertex 0.0 0.0 0.0
vertex 0.0 1.0 1.0
vertex 0.0 1.0 0.0
endloop
endfacet
facet normal -1.0 0.0 0.0
outer loop
vertex 0.0 0.0 0.0
vertex 0.0 0.0 1.0
vertex 0.0 1.0 1.0
endloop
endfacet
facet normal 0.0 1.0 0.0
outer loop
vertex 0.0 1.0 0.0
vertex 1.0 1.0 1.0
vertex 1.0 1.0 0.0
endloop
endfacet
facet normal 0.0 1.0 0.0
outer loop
vertex 0.0 1.0 0.0
vertex 0.0 1.0 1.0
vertex 1.0 1.0 1.0
endloop
endfacet
facet normal 1.0 0.0 0.0
outer loop
vertex 1.0 0.0 0.0
vertex 1.0 1.0 0.0
vertex 1.0 1.0 1.0
endloop
endfacet
facet normal 1.0 0.0 0.0
outer loop
vertex 1.0 0.0 0.0
vertex 1.0 1.0 1.0
vertex 1.0 0.0 1.0
endloop
endfacet
facet normal 0.0 -1.0 0.0
outer loop
vertex 0.0 0.0 0.0
vertex 1.0 0.0 0.0
vertex 1.0 0.0 1.0
endloop
endfacet
facet normal 0.0 -1.0 0.0
outer loop
vertex 0.0 0.0 0.0
vertex 1.0 0.0 1.0
vertex 0.0 0.0 1.0
endloop
endfacet
facet normal 0.0 0.0 1.0
outer loop
vertex 0.0 0.0 1.0
vertex 1.0 0.0 1.0
vertex 1.0 1.0 1.0
endloop
endfacet
facet normal 0.0 0.0 1.0
outer loop
vertex 0.0 0.0 1.0
vertex 1.0 1.0 1.0
vertex 0.0 1.0 1.0
endloop
endfacet
endsolid MYSOLID
The same cube imported in Tinkercad
A sphere would then be composed of hundreds, if not thousands, of triangles depending on the precision of its surface. Luckily, there is software to calculate this!
3D Printing at the Library
Did you know? Your library offers low-cost 3D printing services!
Loyal to our mission to support teaching and research, we want to make this innovative technology accessible for its high educational and social potential.
Visit the 3D Printing page for more information.
Resources
Beginning Design for 3D Printing - 
This link opens in a new window
ISBN: 9781484209479Publication Date: 2015Access limited to 1 user at a time.
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