Hi,
I've seen your post on TAU concerning TA2. This is exactly what we're trying to do here (much more than Spring which is now a RTS TA like game engine). TA3D started as a small experiment 4 years ago and has grown up with less developers than Spring : no more than 3 at the same time, something like 2 years with me as the only developer! Now we are a small team (2 programmers, testers, people writing translations, docs, ...) but development is still slow compared to the huge amount of things to do (to give an idea of the task, TA3D itself, not the tools, is something like 85k lines of code). If you are willing to help us, we'll be glad to welcome you in the team
All released packages (that are not too old) are available from
ftp://downloads.ta3d.org/binaries/
Latest alphas have been released only for windows (they are simple 7zip archives, just use 7zip to extract them), for both Linux and OS X you'll need to build the code from SVN if you want to try the 0.6.x branch (packages are available for Ubuntu and Mandriva only for stable releases like 0.5.x).
If you have any question, feel free to ask.