Poison Ivy...

Play testing with the Ivy Generator by Thomas Luft & 3D Studio.

for more info: http://graphics.uni-konstanz.de/~luft/ivy_generator/

But today i found that there is a modified version that takes full advantage of multi-core processors instead of only one core in the original program.

The new version is called Ivy generator 2012 and can be found here: http://vivec3d.com/3d-ivy-generator-2012/