What is 3D printing?
3D printing, or additive manufacturing, is a process of making three dimensional solid objects from a digital file. The creation of a 3D printed object is achieved using additive processes. In an additive process an object is created by laying down successive layers of material until the entire object is created. Each of these layers can be seen as a thinly sliced horizontal cross-section of the eventual object.
How does 3D printing work?
It all starts with making a virtual design of the object you want to create. This virtual design is made in a CAD (Computer Aided Design) file using a 3D modeling program (for the creation of a totally new object) or with the use of a 3D scanner (to copy an existing object). A 3D scanner makes a 3D digital copy of an object.
3d scanners use different technologies to generate a 3d model such as time-of-flight, structured / modulated light, volumetric scanning and many more.
Recently, many IT companies like Microsoft and Google enabled their hardware to perform 3d scanning, a great example is Microsoft’s Kinect. This is a clear sign that future hand-held devices like smartphones will have integrated 3d scanners. Digitizing real objects into 3d models will become as easy as taking a picture. Prices of 3d scanners range from very expensive professional industrial devices to 30 USD DIY devices anyone can make at home.
Other things to be careful of when creating your model:
3D Modeling Resources:
OpenSCAD - free software for creating solid 3D CAD models. Useful for creating models of machine parts.
Tinkercad - a browser-based 3D design platform, now part of Autodesk (free version available).
123D Design - a free, powerful, yet simple 3D creation and editing tool from Autodesk.
List of additional free software packages from 3ders.com.
You can search for pre-existing models on the Internet to print as they are, or to modify using 3D modeling software.
3D Warehouse - Sketchup's searchable design library.
Instructables - from the 123D community.
Thingiverse - MakerBot's searchable design library community.
3D modeling for beginners (Shapeways)
How do I make a solid model (Rhino)
How to fix and repair your 3D files (Shapeways)