I'd like to create a lisp function which waits for the user to specify a point which lies on a straight line passing through a specified point and inclined of a specified angle. It's not difficult to code but the function must show a rubber-line which moves only along the specified angle.

I already coded such a function. Here it is:

(defun getpolar (pt ang msg / r)

  (vl-cmdf "_line" pt (strcat "<" (angtos ang (getvar "AUNITS"))))

  (prompt msg)

  (command pause)

  (command)

  (setq r (getvar "LASTPOINT"))

  (entdel (entlast))

  (polarp pt ang (* (distance r pt) (cos (- (angle pt r) ang))))

)

Try it like this:

(getpolar '(0 0 0) 30 "Specifiy end point: ")

But I want the function not to create a line entity and then delete it.

Is there a simpler way?

For example, if from command-line I enter:

(getpoint '(0 0 0) "Specifiy end point: ")

and then:

<45

a rubber-line which moves only along an angle of 45° appears.

But how do I put it in a lisp function?

Thanks to all.