Lsystem surface

Im working on being able to draw lsystem curves across a surface. The code is based on the example lsystem ghx on the rhino web site with some modification and code added to the orginal. This is a little rough.

I would like to have greater control as to were the curves ar being drawn on the surface. I would also like to add a function that bases the curves interms of density and direction based on the curvature of the surface. Any one that has any thoughts please help.

I would like to use this to develop no linear stucture as well as a way to panalize a surface.