chrisd:

... however, PhotoFly
1. requires a license of an Autodesk product (as in not free)
2. license is non-commercial (as in don't use this if you want to use it for something other than play)

Where did you get that from? It is free and it is licensed for commercial use. There's just a warning that it's not production software (read beta) so there are no guarantees. It's a standalone product.

The download is a "scene editor" that is used to edit a scene/add photos/etc. It then sends the photos to an Adsk server that does all of the number crunching which in turn sends an email to download the *.rzi or *.3dp file which tells your Scene Editor how the photos are organized/arranged and where the point cloud is and all of the mesh data.