These two programs help to find the first or the last point of an entity (for POLYLINE, LWPOLYLINE, SPLINE, LINE, ARC).

Nikolai Poleshchuk

;CODING STARTS HERE
;**********************************************************************
;**** In the current coordinate system, find the first point of
;**** an entity of type LINE, POLYLINE, LWPOLYLINE, ARC, or SPLINE.
;**** V.Savelieva, 2000
;**********************************************************************
;**** No globals.
;**** No arguments.
;**** The locals:
;**** w - the list returned by the entsel function;
;**** e - the specified entity;
;**** le - the list of the e entity;
;**** ten - the type of the e entity;
;**** ca10 - the value of the dotted pair (DXF code is 10);
;**** pt - the point to be found.
;**** The return value:
;**** a list of three coordinates of the points or nil
;**** (if an entity of another type was specified).
;**********************************************************************
;
(defun ffp ( / w le e ten ca10 pt)
; Request for an object
(setq w
(entsel
"\nSpecify an object of type LINE, ARC, POLYLINE, LWPOLYLINE, or SPLINE: "
);entsel
)
; Check if an object is specified
(while (null w) (setq w (entsel "\nNo object is selected, repeat: ")))
; Read the entity's data, get the values for the DXF codes 0 and 10
(setq
le (entget (setq e (car w)))
ten (cdr (assoc 0 le))
ca10 (cdr (assoc 10 le))
);setq
; Display the type of the entity
(princ (strcat "\n" ten " "))
; Find the first point of the object in its own coordinate system
(setq pt
(cond
; LINE and SPLINE
((or (= ten "LINE")(= ten "SPLINE")) ca10)
; LWPOLYLINE (append the third coordinate to ca10)
((= ten "LWPOLYLINE") (append ca10 (list (cdr (assoc 38 le)))))
; ARC (find the point by the center, the radius, and the angle
((= ten "ARC")
(list
(+
(car ca10)
(* (cdr (assoc 40 le)) (cos (cdr (assoc 50 le))))
);+
(+
(cadr ca10)
(* (cdr (assoc 40 le)) (sin (cdr (assoc 50 le))))
);+
(caddr ca10)
);list
)
; POLYLINE (read the first vertex of the polyline)
((= ten "POLYLINE")(cdr (assoc 10 (entget (entnext e)))))
; For all other types display a message and return nil
(T
(princ "\nInvalid entity type. ")
nil
);T
);cond
);setq pt
; Transform the coordinates to the current UCS
(if pt (trans pt e 1))
);defun
;CODING ENDS HERE

;CODING STARTS HERE
;**********************************************************************
;**** In the current coordinate system, find the last point of
;**** an entity of type LINE, POLYLINE, LWPOLYLINE, ARC, or SPLINE.
;**** V.Savelieva, 2000
;**********************************************************************
;**** No globals.
;**** No arguments.
;**** The locals:
;**** w - the list returned by the entsel function;
;**** e - the specified entity;
;**** le - the list of the e entity;
;**** ten - the type of the e entity;
;**** ca10 - the value of the dotted pair (DXF code is 10);
;**** pt - the point to be found.
;**** The return value:
;**** a list of three coordinates of the points or nil
;**** (if an entity of another type was specified).
;**********************************************************************
;
(defun flp ( / w e le ten ca10 e1 pt)
; Request
(setq w
(entsel
"\nSpecify an object of type LINE, ARC, POLYLINE, LWPOLYLINE, or SPLINE: "
);entsel
);setq
; Check if an object is specifie
(while (null w) (setq w (entsel "\nNo object is selected, repeat: ")))
; Read the entity's data
(setq
le (entget (setq e (car w)))
ten (cdr (assoc 0 le))
ca10 (cdr (assoc 10 le))
)
; Display the type of the entity
(princ (strcat "\n" ten " "))
; Find the last point of the object in its own coordinate system
(setq pt
(cond
; LINE
((= ten "LINE") (cdr (assoc 11 le)))
; SPLINE
((= ten "SPLINE") (cdr (assoc 10 (reverse le))))
; LWPOLYLINE (append the third coordinate)
((= ten "LWPOLYLINE")
(append
(if (= 1 (cdr (assoc 70 le))); closed?
ca10; last = first
(cdr (assoc 10 (reverse le)))
);if
(list (cdr (assoc 38 le)))
);append
);LWPOLYLINE
; ARC (find the point by the center, the radius, and the angle
((= ten "ARC")
(list
(+
(car ca10)
(* (cdr (assoc 40 le)) (cos (cdr (assoc 51 le))))
);+
(+
(cadr ca10)
(* (cdr (assoc 40 le)) (sin (cdr (assoc 51 le))))
);+
(caddr ca10)
);list
);ARC
; POLYLINE (read the vertices of the polyline up to the SEQEND entity
((= ten "POLYLINE")
(if (= 1 (cdr (assoc 70 le))); closed?
(cdr (assoc 10 (entget (entnext e)))); last=first
(progn
(setq e1 (entnext e))
(while (= "VERTEX" (cdr (assoc 0 (entget (entnext e1)))))
(setq e1 (entnext e1))
);while
(cdr (assoc 10 (entget e1)))
);progn
);if
);POLYLINE
; For all other types display a message and return nil
(T
(princ "\nInvalid entity type. ")
nil
);T
);cond
);setq
; Transform the coordinates to the current UCS
(if pt (trans pt e 1))
);defun flp
;CODING ENDS HERE