Create stepping lwpolyline with getpoint along lines.

[Strydaris]

Hi Everyone,

 

Was hoping someone could help me out with some idea here.

I am not looking for someone to write code for me on this because I want to learn more, but I was hoping someone could push me in the right direction a little bit.

 

I am currently using a piece of code created by Lee Mac for creating a LWpolyline using a list of points.

It looks something like this....

(defun LWPoly (lst)
  (entmakex
    (append
      (list
	(cons 0 "LWPOLYLINE")
	(cons 100 "AcDbEntity")
	(cons 100 "AcDbPolyline")
	(cons 90 (length lst))
	(cons 70 1)
      )
      (mapcar (function (lambda (p) (cons 10 p))) lst)
    )
  )
)

 

 

What I am using this for is to try and create a list of points to draw something like this...

The red lines are the user given lines.

Green lines are the resulting lines created by picking the PTs(points) along the red lines.

The white dashed lines is the constant that the green lines needs to be away from the red lines. This number is 6.

Each vertical rise in the green line is also 6, the run varies due to the angle of the red lines.

 

 

What I am doing is creating conditions for each angle of the selected points.

For example....

(cond ((or (= ang 0)(= ang 180)(= ang 180))
       (setq npt2 (polar pt2 (Degrees->radians 90) 6)
	         pt-list  (append pt-list (list pt2))
	         npt-list (append npt-list (list npt2))
       )
      );END COND 1

I then repeat this type of thing for each condition...

Lower left point to upper right, Upper Right to lower left, Lower RIght to Upper Left and Upper Left to Lower Right.

Then I have a bunch of setq's to do a bunch of trig math to figure out the points I need.

While this seems to be working for the most part, I figured I would ask around to see if anyone had any other ideas to reach the same results.

 

[BIGAL]

Ok dont need a list of points rather calc a point as you go. The image shows plines as insulation these are made by using the normal pline options. I am not sure that the top point will always look like that as a 6 vertical may mean it does not go through that top point. Can you post some samples in a dwg or do you alter the horizontal spacing to force a match. What is the spacing rule ?

 

 

 

[Strydaris]

@Bigal

 

Hey Bigal,

I have attached the CAD file I am testing this in.

The lwpolylines on the left is me testing the lisp so far. first 2 conditions work well but there is an error I want to fix.

I do need to create the list because I need to get the length of the line (pt1 to pt2) so I can divide that by the hypotenuse to get the amount of "Steps" I need to create. then calc and add the left over amount to the end of the polyline.

Here is the code I have so far.

(defun c:flsh3 (/ )
  (setq	npt-list nil
	pt-list	nil
	f-list nil
	ang nil
	angchck nil
	dist nil
	pt1 nil
	pt2 nil
	opp 6
	)

;;Check if layers exist, if not create it
   (if (not (tblsearch "Layer" "WD-Flashing"))
      (entmake (list (cons 0 "LAYER")
		     (cons 100 "AcDbSymbolTableRecord")
		     (cons 100 "AcDbLayerTableRecord")
		     (cons 2 "WD-Flashing");;Layer Name
		     (cons 70 1);;Printable 0=No 1=Yes
		     (cons 6 "Continuous");;Linetype
		     (cons 62 14);;Colour
		     (cons 290 0)
		     (list -3 (list "AcAecLayerStandard" '(1000 . "") (cons 1000 "Working Drawing ONLY -Elevation Flashing. Use background colour 255,255,255 in hatching over brick")))
		     )
	       )
      )
    (setq lay "WD-Flashing"     ;;Sets the layer to be used by the LISP
	  			;;Settings the varibles
	  cl (getvar 'clayer)   ;;Gets the current layer
	  cmd (getvar 'cmdecho)
	  )
    (setvar 'cmdecho 0)
    (setvar 'clayer lay)
;Get the points
    (if (setq pt1 (getpoint "\nSelect First Point of Flashing: "))
		(progn
		    (setq npt1 (polar pt1 1.5708 6)
			  pt-list (append pt-list (list pt1))
			  npt-list (append npt-list (list npt1))
			  )
		    )
	)

    (while (setq pt2 (getpoint pt1 "\nSelect Next Point or [ENTER] to Exit"))
	(setq ang  (angle pt1 pt2)
	      angchck (atoi (rtos (RtD ang) 2 0))
	      dist (distance pt1 pt2)
	      )
;Start the conditions.
	(cond
	    ((or (= angchck 0)(= angchck 180)(= angchck 360))
	     (setq npt2 (polar pt2 1.5708 6)
		   pt-list (append pt-list (list pt2))
		   npt-list (append npt-list (list npt2))
		   )
	     );_cond 1
	    
;;                                         
;;START COND FOR BOTTOM LEFT TO UPPER RIGHT
;;                                         
	    ((and (> angchck 0) (< angchck 90))
	     (setq npt2     (polar pt1 (Degrees->Radians 90) (/ 6 (cos ang)))
		   pt-list  (append pt-list (list pt2));Add the selected points tothe list
		   npt-list (append npt-list (list npt2));Add the new points to the list
		   Adj      (/ Opp (/ (sin ang) (cos ang)))
		   HYP      (sqrt (+ (expt Opp 2) (expt Adj 2)))
		   div      (rtos (/ dist HYP) 2 0)
		   Xdist    (abs (- (car Pt1) (car Pt2)))
		   lftovrx  (- Xdist (* (atoi div) Adj))
		   Ydist    (abs (- (cadr Pt1) (cadr Pt2)))
		   lftovry  (- Ydist (* (atoi div) Opp))
		   )
       (repeat (atoi div)
	 (setq npt3	(polar npt2 (Degrees->Radians 90) opp)
	       npt4	(polar npt3 0 Adj)
	       npt-list	(append npt-list (list npt3) (list npt4))
	       npt2	npt4
	 )
       )
       (setq npt5     (polar npt4 (Degrees->Radians 90) lftovry)
	     npt6     (polar npt5 0 lftovrx)
	     npt-list (append npt-list (list npt5) (list npt6))
       )
      )					;END COND 2
;;                                         
;;START COND FOR UPPER LEFT TO BOTTOM RIGHT
;;
	    ((and (> angchck 270)(< angchck 360))
	     (setq npt2     (polar pt1 (Degrees->Radians 90) (/ 6 (cos ang)))
		   pt-list  (append pt-list (list pt2))
		   npt-list (append npt-list (list npt2))
		   Adj      (/ Opp (/ (sin ang) (cos ang)))
		   HYP      (sqrt (+ (expt Opp 2) (expt Adj 2)))
		   div      (rtos (/ dist HYP) 2 0)
		   Xdist    (abs (- (car Pt1) (car Pt2)))
		   lftovrx  (- Xdist (* (atoi div) (abs Adj)))
		   Ydist    (abs (- (cadr Pt1) (cadr Pt2)))
		   lftovry  (- Ydist (* (atoi div) Opp))
		   )
       (repeat (atoi div)
	 (setq npt3	(polar npt2 (degrees->radians 180) adj)
	       npt4	(polar npt3 (degrees->radians 270) opp)
	       npt-list	(append npt-list (list npt3) (list npt4))
	       npt2	npt4
	 )
       )
       (setq npt3     (polar npt4 (Degrees->radians 270) lftovry)
	     npt4     (polar npt3 (Degrees->radians 360) lftovrx)
	     npt-list (append npt-list (list npt5) (list npt6))
       )
      )					;END COND 3
;;                                         
;;START COND FOR BOTTOM RIGHT TO UPPER LEFT
;;
      ((and (> angchck 90)
	    (< angchck 180)
       )
       (setq npt2     (polar pt1 (Degrees->radians 90) 6)
	     pt-list  (append pt-list (list pt2))
	     npt-list (append npt-list (list npt2))
	     Adj      (/ Opp (/ (sin ang) (cos ang)))
	     HYP      (sqrt (+ (expt Opp 2) (expt Adj 2)))
	     div      (rtos (/ dist HYP) 2 0)
	     Xdist    (abs (- (car Pt1) (car Pt2)))
	     lftovrx  (- Xdist (* (atoi div) (abs Adj)))
	     Ydist    (abs (- (cadr Pt1) (cadr Pt2)))
	     lftovry  (- Ydist (* (atoi div) Opp))
       )
       (repeat (atoi div)
	 (setq npt3	(polar npt2 (degrees->radians 90) opp)
	       npt4	(polar npt3 0 Adj)
	       npt-list	(append npt-list (list npt3) (list npt4))
	       npt2	npt4
	 )
       )
       (setq npt5     (polar npt4 (Degrees->radians 90) lftovry)
	     npt6     (polar npt5 (Degrees->radians 180) lftovrx)
	     npt-list (append npt-list (list npt5) (list npt6))
       )
      );_cond Upper Left


	    );_cond
	
	(setq pt1 pt2)
	);_while
    (setq npt-list (reverse npt-list)
	  F-list (append F-list pt-list npt-list)
	  )
;Draw the polyline, then hatch it.    
  (LWPOLY F-list)
  ;(command "-hatch" "_s" (entlast) "" "_p" "_u" "90" "1" "_n" "_co" "" "_t" "255,255,255" "")

  (princ)
);_defun

(defun LWPoly (lst)			; LM's entmake functions
  (entmakex
    (append
      (list
	(cons 0 "LWPOLYLINE")
	(cons 100 "AcDbEntity")
	(cons 100 "AcDbPolyline")
	(cons 90 (length lst))
	(cons 70 1)
      )
      (mapcar (function (lambda (p) (cons 10 p))) lst)
    )
  )
)

(defun Degrees->Radians	(numberOfDegrees)
  (* pi (/ numberOfDegrees 180.0))
)
    

 

Flashing Test File.dwg