Lisp for automatically mark a triangle for distance between IP points of polyline curves

[nilesh.bhosale]

I have this lisp i want modify it for marking triangle with dimensions refer attached autocad file ......

(defun c:IPMark (/ bulge ptcp pct delta/2 ang chord radius tangent enpi pilst)

(setq en (car (entsel "Select Alignment: "))
lst (listpolb en)
pilst nil
)
(while (> (length lst) 1)
(if (not (zerop (setq bulge (cadar lst))))
(setq ptc (caar lst)
pct (caadr lst)
delta/2 (* (atan bulge) 2.0)
ang (- (angle ptc pct) delta/2)
chord (distance ptc pct)
radius (/ chord (* 2 (sin delta/2)))
tangent (* radius (tan delta/2))
pilst (cons (polar ptc ang tangent) pilst)
enpi (entmakex (list (cons 0 "POINT") (cons 10 (car pilst))))
)
)
(setq lst (cdr lst))
)
(print pilst)
(princ)
)

;; tan From std-lib ;
(defun tan (z / cosz)
(cond ((zerop (rem z pi)) 0.0)
((zerop (rem z (/ pi 2))) 1.7e308)
((zerop (setq cosz (cos z))) 1.7e308)
(t (/ (sin z) cosz))))


;; ;
;; listpolb by ymg ;
;; ;
;; Parameter: en, Entity Name or Object Name ;
;; ;
;; Returns: List of Points and Bulge in WCS ;
;; ;
;; Notes: On Closed Polyline the Last Vertex is Same as First) ;
;; ;

(defun listpolb (en / obj i p l)
(if (= (type en) 'ENAME)
(setq obj (vlax-ename->vla-object en))
(setq obj en en (vlax-vla-object->ename en))
)
(repeat (setq i (fix (vlax-curve-getEndParam en)))
(setq l (cons (list (vlax-curve-getPointAtParam en (setq i (1- i)))
(vla-getbulge obj i)
)
l
)
)
)
(if (= (vla-get-closed obj) :vlax-true)
(append l (list (car l)))
l
)
)

[Kent1Cooper]

An interesting concept....  But there's something wrong at IP-8.  All the other IPs are APParent intersections between two line segments on either side of an arc segment [whose midpoint is near the IP].  But IP-8 is at a vertex between line segments, with no arc segment in the neighborhood.  If both situations are possible, it's a hugely more complex problem than if every IP is like the others, off the Polyline near the midpoint of an arc segment that is flanked by two line segments.

[nilesh.bhosale]

The dimension of 1st IP & the Last IP point on polyline need to be taken from the start of the polyline and the end of the polyline respectively 

[nilesh.bhosale]

The drawing is updated, it was a mistake there will be always a curve on polyline

[Sea-Haven]

Having done road design for to many years it is a common thing to not put a curve between changes of grade, where the change is less than a certain value, you would not do it on a freeway but a low speed road can push up to about 2% with no curve, so Kent your right would be a problem as no curve. Talking about curves in road design they are normally not curves but rather "Vertical Curve" which is a parabola. The road surface is normally a pline with short segments to reflect the parabola. So again finding the IP is a problem.

The poster refers to Vertical so its not a horizontal alignment.

[nilesh.bhosale]

This is not road layout this is for mining bulk materials handling technological layouts so it is a different concept I need to mark triangle of IP for curves marked on polyline as shown in attached drawing

[Sea-Haven]

Ok

[CADaSchtroumpf]

A try with this...

The list returned by code is inclined, horizontal ans vertical dimension.

For continued you can use a block with attributes filled in by the list of values

(vl-load-com)
(defun c:IPMark ( / js AcDoc n ename obj pr dist_start dist_end pt_start pt_end seg_len seg_bulge rad alpha pt_vtx lst_pt)
  (princ "\nSelect Alignment: ")
  (while (null (setq js (ssget "_+.:E:S" '((0 . "LWPOLYLINE")))))
    (princ "\nIsn't a polyline!")
  )
  (setq AcDoc (vla-get-ActiveDocument (vlax-get-acad-object)))
  (vla-StartUndoMark AcDoc)
  (setq
    ename (ssname js 0)
    obj (vlax-ename->vla-object ename)
    pr -1
  )
  (repeat (fix (vlax-curve-getEndParam obj))
    (setq
      dist_start (vlax-curve-GetDistAtParam obj (setq pr (1+ pr)))
      dist_end (vlax-curve-GetDistAtParam obj (1+ pr))
      pt_start (vlax-curve-GetPointAtParam obj pr)
      pt_end (vlax-curve-GetPointAtParam obj (1+ pr))
      seg_len (- dist_end dist_start)
      seg_bulge (vla-GetBulge obj pr)
    )
    (if (not (zerop seg_bulge))
      (setq
        rad (/ seg_len (* 4.0 (atan seg_bulge)))
        alpha (+ (angle pt_start pt_end) (- (* pi 0.5) (* 2.0 (atan seg_bulge))))
        pt_vtx (polar pt_start (- alpha (* pi 0.5)) (* rad (/ (sin (* 2.0 (atan seg_bulge))) (cos (* 2.0 (atan seg_bulge))))))
        lst_pt (cons pt_vtx lst_pt)
      )
    )
  )
  (cond
    (lst_pt
      (mapcar '(lambda (x) (entmakex (list (cons 0 "POINT") (cons 10 x)))) lst_pt)
      (print (mapcar '(lambda (x y) (list (distance x y) (- (car x) (car y)) (- (cadr y) (cadr x)))) lst_pt (cdr lst_pt)))
    )
  )
  (vla-EndUndoMark AcDoc)
  (prin1)
)

[john.uhden]

Finding the IP, or PI, or PVI is all the same to me.

It's just the intersection of the straight tangents.

It doesn't matter whether they are connected by a circular curve or a parabola.

In fact, relying on the bulge value can be erroneous if the curve is not tangent.

[nilesh.bhosale]

yes it is working and showing results in List (by pressing F2 command)

but i am unable to make attribute blocks with filled to put these values in triangle form in the drawing.

i have attached here the drawing where i have tested this code  

[CADaSchtroumpf · Accepted solution]

Try this

If the block doesn't exist it's created

You can move the block if the insertion isn't not at good place (middle point bettwen of the IP by defaut)

[nilesh.bhosale]

Amazing...!!!

Dear Sir,

Thank you very much this is fabulous working perfectly fine

thanks again

[nilesh.bhosale]

i cant resist myself to ask further more...,

can i get the angle also, along with the this triangle?? (sin@) of right angle triangle formed from IP points?

sample file attached 

[john.uhden]

@nilesh.bhosale and @CADaSchtroumpf 

I'm not sure what was supposed to happen, but I must caution you again that the bulge does not necessarily tell you where the PI is, as the curve may not be tangent at both ends.  That's what we call a "broken back curve."  You should intersect the previous and subsequent straight tangents.

[CADaSchtroumpf]

@john.uhden 

You're right, but when we do road design (which seems to be the case), we avoid making non-tangent connections or you given it a good steering wheel !)🤕

[john.uhden]

@CADaSchtroumpf

I am a civil as well, and would nver create a broken back curve, but ,hey,
you never know what someone else may have done before you got the drawing.
Like today I studied the site photos and found that the sanitary manhole is
actually a DOT manhole and that the nearby sanitary manhole was never
located. Now the field crew has to go back out and locate it. 😕

[CADaSchtroumpf · Accepted solution]

Before test in your drawing, you must erase all INSERT with name "BLK_MEASURE_CURVE"

Purge this block and after test the lisp.

[CADaSchtroumpf]

@john.uhden 

You just have to have common sense! ...
Applying your method will complicate the code a lot and in the event of a counter curve without a straight element between, how do we do it (especially if they are broken)?
For me both methods have their flaws.

[john.uhden]

@CADaSchtroumpf
Complicated code is the name of my game. I could show you some of my
larger works, but it would create nausea. 😱
But you are correct... the user must eliminate the flaws before using code
that expects flawless conditions.

[CADaSchtroumpf]

---

@john.uhden  a écrit :
@CADaSchtroumpf
Complicated code is the name of my game. I could show you some of my
larger works, but it would create nausea. 😱

---

@john.uhden 

This is also my case, I made routines for AutocadMap which automatically calculate and fill OjectData.

It took me a lot time to develop them, but they enabled me to establish a functional GIS (from A to Z) in record time.

They are so specific that I will certainly never publish them because to make them generic there would still be a lot of work.