Here my code to create line from point at red line to perpendecular of white color line, but that code is still trouble, it can not work
and look at attach file for clear information
(defun c:test ()
(if
(setq ssc (car (entsel "\nClick red color line")))
(progn
(setq ssw (entsel "\nClick white color line"))
(setq dis 25)
(command "_divide" ssc dis "")
(setq ssp (ssget "x" (list (cons 0 "POINT"))))
(setq sslp (sslength ssp))
(setq cnt1 0)
(repeat
sslp
(setq pn (ssname ssp cnt1))
(setq sse_pn (entget pn))
(setq sp_pn (cdr (assoc 10 sse_pn)))
(setq lst_pkn (append lst_pkn (list sp_pn)))
(setq cnt1 (1+ cnt1))
) ; repeat
(setq lst_pn (reverse lst_pn))
(setq len1 (length lst_pn))
(setq cnt2 0)
(repeat
len1
(setq pt1 (nth cnt2 lst_pkn))
(setq om (getvar "osmode"))
(setvar "osmode" 128)
(setq pt2 (osnap (cadr ssw) "_perp"))
(command "_line" pt pt2 "")
(setvar "osmode" om)
(setq cnt2 (1+ cnt2))
) ; repeat
) ; progn
) ; if
(princ)
) ; defun