3D Push is a free iOS app that lets a user visualize a STL file on an iPod, iPhone or iPad. The STL file can be an email attachment or located on a website like Thingiverse. The app also enables the user to
1) Upload the STL file to their Dropbox.
2) Visualize the 3D object in different colors.
3) Take a snapshot of the 3D object and store it in the photo library.
The STL file format is the most common format used for 3D printing. Using this app a user can inspect all of the aspects of the 3D object on his or her iDevice before printing it out on a 3D printer.
NOTE: In addition to the sample STL provided, the app lets a user visualize STL files that are attached to an email or STL files located on the web.