A public beta version of TopoGun 3 is now available.
You can now visit the new product website and download the beta, then launch it in demo mode. If you have a license of TopoGun 2 you can use your existing serial number to activate the new version.
The new version mixes manual and semi-automated retopology features letting you paint masks and split a sculpt into separate meshes. You can draw guide curves to control the flow of edges generated automatically.
There's also a new Patch tool that can be used to sketch out major regions of a sculpt following anatomical landmarks for TopoGun to generate new topology automatically. You can then use these patches and combine them to create a new low-poly surface for the entire model.
You can learn more here.