The Autodesk 360 free mobile device viewer application gives you a productive tool for use in the field. You can view, comment, annotate and share 2D and 3D files.
This mobile application supports 2D & 3D DWG, DWF, Revit, and Navisworks files.
The benefits are many. While viewing your project design files, you can add comments & suggestions for design changes. Sharing with the extended team is easy with this free application - no need to have additional licenses. This app can also help you go "paperless" while at the same time providing universal access to design information and, of course, you can accelerate the design review process for the entire team.
More information on the Autodesk 360 free mobile viewer application is available here. And it is easy to download from the Apple AppStore or GooglePlay.