Ah, cool. Makes sense. The Nervous stuff (I am pretty sure) is derived from the algorithms outlined here: http://algorithmicbotany.org/papers/venation.sig2005.pdf It's a fantastic paper, and totally possible to implement. A number of folks here have done so, I believe.

See this also might help you ...

http://www.grasshopper3d.com/forum/topics/space-colonization-algorithm

Thanks for the links, I will look to them.

I already looked to some venations examples and to my point of view it is important to have a direction of growth. So I think geodesic could be useful, growth will be perpendicular to iso geodesic distances. Here is an exemple with horse, I put points on horse sabots (main veins will begin here)