On the Downloads page, find the link to the SB Navmesh Builder. This handy tool lets you create a list of *.TER map files to which you want to add a nav mesh. Once that you start it, it will automatically process the list of files without further input needed, so you can spend the time with things that are more fun than to stare up to 20 minutes at a progress bar – per map!
SB Navmesh Builder lets you select the number of threads so that your multi-core processor can convert multiple map files simultaneously. Consumes more electricity but gets you there faster, especially if you have a long list of maps that you want to convert. Oh, yeah: Only recommended if you have plenty of RAM. The individual conversion may require 3.5 GByte (in rare cases even more), on average maybe 1 GByte per conversion run. So this only makes sense if you have a 64 bit Windows, plenty of RAM, and a multi-core processor.
Those maps that consume more than 3.5 GByte of RAM will probably fail to convert and rather crash the instance of SB Pro. Sorry about that, you’ll have to wait until a 64 bit version of SB Pro comes out. We don’t think that this will happen frequently, however. Also, the Windows Task Manager may show the instances of SB Pro as “unresponsive” during extended time periods of the conversion process. Don’t worry. The computer is just very, very busy.
Update
The version 5 that was offered two days ago turned out to be less reliable than expected. We have updated the downloads page, and version 6 will at least no longer overwrite an existing *.TER file if the converted one has a zero byte count.