What is picogen?
picogen is an outdoor ray tracing system, targetting large-scale terrain with realistic day/night-illumination and detailed plant populations.
Licensed under GPL, v3 or later: http://www.gnu.org/licenses/gpl.html.
Have a look at the downloads.
Additional news sources
Jump onto the picogen deviantART
train group at http://picogen.deviantart.com.
Picogen on freshmeat is here: http://freshmeat.net/projects/picogen/.
You can find several statistics about the development of picogen on http://ohloh.net:
For acquiring source code, see the following section.