This project converts an SVN repository into multiple Git repositories, optionally registering each repository as a submodule in some other Git repository. It started out as KDE's svn2git tool, but has been almost completely rewritten, to the point where very little of the original code remains.
There were many reasons for our initial deviations from svn2git, but the heart of the original program was still there until we discovered it was producing nonsense results. When we evaluated the core logic, it became clear that the svn2git approach was insufficiently general to correctly handle our branch and directory mapping structure. Our rewrite requires C++11.
In the rewrite, we dropped several features of svn2git that aren't needed for Boost, most notably incremental conversions. The dropped features could be brought back without too much difficulty, but unless someone else takes over maintenance of this project, they are unlikely to get addressed. The issue tracker is our record of what can or should still be done.
For any substantially large SVN-to-Git conversion + modularization job, if you start with today's technology, some amount of coding will be necessary. Because it is quite general and fairly clean, Boost2Git is probably a good starting point.