Are there any software packages that can open and edit 3MF? I am trying to find programs that can import and export 3MF file formats. I know that Cura 15.10 beta can open 3MF formats, but I am looking for a program that open, edit and save 3MF files. I am very interested in finding a more portable file format for my 3D designs.

If you are not aware the 3MF format promises to provide a "replacement" for STL files that contains the complete model information, theoretically allowing us to slice and edit the same file.

http://3mf.io/
Microsoft 3D Builder should have support for this format.

Solidworks 2015 has support too. A software adoption list is placed on 3mf pages.