3D models can be created and modified using Computer Aided Design (CAD) software.  Various versions of paid and free CAD software are listed below:

Online 3D design collections

Collections of finished 3D designs can be found online. You may be able to freely download and use the designs for 3D printing under the Creative Commons Licence.

Museum collections

Some museums are now making parts of their collections available as scans for home 3D printing.  

Please note that not all of the scans available on these websites will be printable at the Library due to the time and complexity of the models.