Curve surface intersection

Hi all,

I am experiencing a problem with the rhinoscript command "curvesurfaceintersection".

I think it may be related to tolerance but I haven't figured out how to solve it.

If you look at the file below I have an exploded box (which I created and exploded) and I am taking the border of one side and checking the intersection with one of the adjacent faces. I would expect that the intersection between the curve and the face on the other side of the edge would be a line (and this happens with the rhino command "intersect" even if sometimes I have experience the same problem with it), but apparently rhino curvesurfaceintersection is giving me multiple intersections among which a series of points. 

Have you have ever experienced a problem like this? If it is a tolerance problem how do you think I should set the tolerance? I tried to change the document tolerance but haven't succeeded.

Any suggestion? 

Thanks in advance for your help

Here is the code (just a simple intersection)

import rhinoscriptsyntax as rs

crv = rs.GetObject("crv",4)
srf = rs.GetObject("srf",8)

intersect = rs.CurveSurfaceIntersection(crv,srf)

print intersect