Creation of vertex at an angle to a curve

I am trying to generate a geometry and then add some curves into it.
It is required to generate a curve and then add a vertex onto the surface at an angle of 120 degree. This vertex should lie on the edge of of the surface and can fall into any curve but the angle should be maintained. I used the following code but could not figure out how to add the direction at a location properly.

[code]reset
merge tolerance 1e-07

create vertex -0.398975 -0.720716 0.01
create vertex -0.416808 -1.1702 0.01
create vertex -0.971347 -0.720148 0.01
create vertex -0.466283 -1.15842 0.01
create vertex -0.749762 -0.445643 0.01
create vertex -0.947087 -0.753945 0.01
create surface vertex 2 4 6 3 5 1

surface 1 copy scale x 0.95 y 0.95 z 1 about -0.685161 -0.807921 0.01

create vertex -0.685161 -0.807921 0.01
create vertex -0.453726 -1.14649 0.01
create vertex -0.705609 -0.948769 0.01
create vertex -0.945514 -0.74059 0.01
create vertex -0.851785 -0.594147 0.01
create vertex -0.579908 -0.594417 0.01
create vertex -0.421755 -0.938581 0.01

create curve vertex 13 15

create vertex location fire ray location surface 1 direction y at curve 13 swing axis y angle 120
[/code]

Any assistance or suggestion is highly appreciated. Regards.

Where is the last vertex to be created on Surf 2? Is the vertex to be at the intersection of curve 13 and 8?

The last vertex needs not to be at the interface or in the middle of any curve. That I have figured out. The last vertex should be generated at an angle to curve 13 where the ray touches the surface 2. What I yesterday tried is

draw direction curve 13 at  -0.685161 -0.807921 0.01 rotate about y 0  rotate about z 120  

With draw direction the direction is generated perfectly on the screen. The direction to be precise is 120 degrees from the curve 13 in the plane. Now where this ray touches the end of surface 2, be it middle or end of a curve, a vertex should be generated. So I tried to use the above generated direction by it did not work.

create vertex at surface 2 location fire ray location direction curve 13 about -0.685161 -0.807921 0.01 rotate about y 0 rotate about z 120 [/code]

Here for clarity I am posting the complete code again.

thank you for your quick reply in the first place.