Topic: Geometry problem: length of segments knowing the area, perimeter and width

[GP]

My attempt 

[owenwengerd]

I think it would be best to withhold your solutions until Marco has tried on his own, else you deny him the opportunity to learn from the experience.

[Marc'Antonio Alessi]

I think it would be best to withhold your solutions until Marco has tried on his own, else you deny him the opportunity to learn from the experience.

you're right, I was trying but I would never have done such a thing!

[Marc'Antonio Alessi]

My attempt 

this is not an attempt but it is much more        tomorrow I'll try as soon as possible...
 

[ribarm]

My attempt is like Owen described in a few steps... No need for using additional routine...
Minimally tested...

Code: [Select]

(defun c:STL-all ( / vk_IsPointInside chk2ptcitouch ss le tl i lw ar ll ptlst ptlstn d1 d2 d3 d4 mitter )

  (defun vk_IsPointInside ( Point PointsList / PY P1Y P2Y )
  ; works with polygons only, i.e. if (equal (car PointsList) (last PointsList))
    (if (cdr PointsList)
      (/= (and (or (and (<= (setq PY  (cadr Point)
                                  P2Y (cadadr PointsList)
                                  P1Y (cadar PointsList)
                            )
                            PY
                        )
                        (< PY P2Y)
                    )
                    (and (> P1Y PY) (>= PY P2Y))
                )
                (> (car Point)
                    (+ (* (/ (- PY P1Y) (- P2Y P1Y))
                          (- (caadr PointsList) (caar PointsList))
                       )
                       (caar PointsList)
                    )
                )
          )
          (vk_IsPointInside Point (cdr PointsList))
      )
    )
  )

  (defun chk2ptcitouch ( p r lw / p1 p2 p3 p4 chk ) (vl-load-com)
    (setq p1 (mapcar '+ (list (car p) (cadr p) 0.0) (list r 0.0 0.0)))
    (setq p2 (mapcar '+ (list (car p) (cadr p) 0.0) (list (- r) 0.0 0.0)))
    (setq p3 (mapcar '+ (list (car p) (cadr p) 0.0) (list 0.0 r 0.0)))
    (setq p4 (mapcar '+ (list (car p) (cadr p) 0.0) (list 0.0 (- r) 0.0)))
    (setq chk 0)
    (if (vlax-curve-getparamatpoint lw p1) (setq chk (1+ chk)))
    (if (vlax-curve-getparamatpoint lw p2) (setq chk (1+ chk)))
    (if (vlax-curve-getparamatpoint lw p3) (setq chk (1+ chk)))
    (if (vlax-curve-getparamatpoint lw p4) (setq chk (1+ chk)))
    (if (eq chk 2) T nil)
  )
 
  (prompt "\nSelect all square-tube LWPOLYLINES")
  (setq ss (ssget (list '(0 . "LWPOLYLINE") '(-4 . "<or") '(70 . 1) '(70 . 129) '(-4 . "or>")
                  )
           )
  )
  (while (null ss)
    (prompt
      "\nEmpty sel.set... Please try selecting all square-tube LWPOLYLINES again..."
    )
    (setq ss (ssget (list '(0 . "LWPOLYLINE") '(-4 . "<or") '(70 . 1) '(70 . 129) '(-4 . "or>")
                    )
             )
    )
  )
  (initget 7)
  (setq le (getdist "\nPick or specify conduit width : "))
  (setq tl 0.0)
  (setq d1 (list le le))
  (setq d2 (list (- le) le))
  (setq d3 (list le (- le)))
  (setq d4 (list (- le) (- le)))
  (repeat (setq i (sslength ss))
    (setq lw (ssname ss (setq i (1- i))))
    (command "_.AREA" "_O" lw)
    (setq ar (getvar 'area))
    (setq ll (/ ar le))
    (setq ptlst (mapcar 'cdr
                        (vl-remove-if-not
                          '(lambda ( x ) (eq (car x) 10))
                          (entget lw)
                        )
                )
    )
    (setq ptlstn (reverse (cons (car ptlst) (reverse ptlst))))
    (setq mitter 0)
    (foreach pt ptlst
      (if
        (cond
          ( (and
              (vl-some '(lambda ( x ) (equal (mapcar '+ pt d1) x 1e-5)) ptlst)
              (vk_IsPointInside (mapcar '+ pt (mapcar '/ d1 (list 2.0 2.0))) ptlstn)
              (chk2ptcitouch (mapcar '+ pt (mapcar '/ d1 (list 2.0 2.0))) (/ le 2) lw)
            )
            T
          )
          ( (and
              (vl-some '(lambda ( x ) (equal (mapcar '+ pt d2) x 1e-5)) ptlst)
              (vk_IsPointInside (mapcar '+ pt (mapcar '/ d2 (list 2.0 2.0))) ptlstn)
              (chk2ptcitouch (mapcar '+ pt (mapcar '/ d2 (list 2.0 2.0))) (/ le 2) lw)
            )
            T
          )
          ( (and
              (vl-some '(lambda ( x ) (equal (mapcar '+ pt d3) x 1e-5)) ptlst)
              (vk_IsPointInside (mapcar '+ pt (mapcar '/ d3 (list 2.0 2.0))) ptlstn)
              (chk2ptcitouch (mapcar '+ pt (mapcar '/ d3 (list 2.0 2.0))) (/ le 2) lw)
            )
            T
          )
          ( (and
              (vl-some '(lambda ( x ) (equal (mapcar '+ pt d4) x 1e-5)) ptlst)
              (vk_IsPointInside (mapcar '+ pt (mapcar '/ d4 (list 2.0 2.0))) ptlstn)
              (chk2ptcitouch (mapcar '+ pt (mapcar '/ d4 (list 2.0 2.0))) (/ le 2) lw)
            )
            T
          )
          ( T nil )
        )
        (setq mitter (1+ mitter))
      )
    )
    (setq tl (+ tl (+ ll (* le (/ mitter 2)))))
  )
  (prompt
    "\nTotal length of all square-tube LWPOLYLINES is : "
  )
  (princ (rtos tl 2 50))
  (princ)
)

Your turn for testing...
Kr. M.R.

[Marc'Antonio Alessi]

My attempt 

Very well, the program is slow because it performs a very complex calculation, I have to review something for use with polylines with "straight" vertices and with width of the conduit is not perfect (249.9999).
Grazie ancora!

My attempt is like Owen described in a few steps... No need for using additional routine...
Minimally tested...
...
Your turn for testing...
Kr. M.R.

This is very fast, I have to review something for use with polylines with "straight" vertices and for lenth of the conduit equal to width (see my dwg).
Grazie mille for your time.

[ribarm]

Hi Marc'... I've changed my code to include cases when segment lengths are the same as conduit width... Try my code updated above and test it to see if everything's OK...

Kr. M.R.

[Marc'Antonio Alessi]

Hi Marc'... I've changed my code to include cases when segment lengths are the same as conduit width... Try my code updated above and test it to see if everything's OK...

Kr. M.R.

Grazie ancora, I need few days to test, now I have new problems to solve...
Ciao.

[Marc'Antonio Alessi]

Hi Marc'... I've changed my code to include cases when segment lengths are the same as conduit width... Try my code updated above and test it to see if everything's OK...

Kr. M.R.

Hi Marko, with a "little" delay I finally managed to try fully your solution and it works perfectly. I just have to add the option to have width of the conduit is not accurate (249.9999).
Thanks again.     Marco