Copyright

Where a digital file of a book, a scan of a book, and a physical copy of a book are usually all considered equivocal copies by Copyright law, the same cannot always be said in the world of 3D printing.  Copyright may protect the design of a 3D object, the file that the printer and program use to create the object, and the final object in different ways.

Are you beginning with a scan of a pre-existing object?

• Did you create this object and retain copyright? (only copyright owners may copy, transform and disseminate their creations without permissions or applying an exception in copyright law; if you did not create the object and/or own copyright, you may need to obtain permissions if the object is still protected by copyright)
• Is the object protected by copyright?  Is it wholly useful or in the public domain?  (Keep in mind that useful objects, or the useful components of objects with both useful and aesthetic characteristics are not protected by copyright.)
• Is the object protected by other intellectual property laws?  (Useful objects, or the useful components of objects with both useful and aesthetic characteristics may be protected under other intellectual property laws, like patent law.)

Are you beginning with a design file created by someone else?

• Is the design file protected by copyright or other intellectual property laws? (A design file for a useful object may be protected by copyright even if the 3D printed object is not.)
• Is the file licensed under Creative Commons or other licensing mechanism that allows your use? (When using material that has been issued with a CC license, you use must abide by the license terms; if the license does not permit commercial use, you will not be able to sell your work.)

Are you intending to sell or license your 3D projects?

• Is it a useful object?   (Useful objects, or the useful components of objects with both useful and aesthetic characteristics are not protected by copyright )
• You will only be able to control the copying, display and dissemination of objects or parts of objects that are protected by copyright.

Your answers to these questions will help you determine whether you need to request permissions from the copyright owner and define what rights you will have as the creator of your 3D printed work. 

These are articles and informative sites that explore how copyright applies to 3D printed objects and the process of 3D printing.