Get bearings of a set of Polylines/Block perpendicular to a given polyline/curve

[chubbyowl]

I have a polyline (red, chainage) and I used measure to put block (perpendicular line) at every 5m of the line. I am looking for way to get the bearing of each of this block faster way. Right now I get each angle one by one.

 

Can anyone please help me get the bearings/angle of each polyline perpendicular to the red line?

I attached an image and dwg for your reference.

 

Thanks so much

Curve.dwg

[BIGAL]

If you look at any of  the Chainage.lsp code that is out there, you will find a mention of vlax-curve-getfirstderiv here is an example defun for each point. 

 

(defun alg-ang (obj pnt)
  (angle '(0. 0. 0.)
     (vlax-curve-getfirstderiv
       obj
       (vlax-curve-getparamatpoint
         obj
         pnt
       )
     )
  )
)