Scaling Polyline Contours

[Bill_Myron]

I have a great request. I need to scale some polyline contours from ground to grid coordinates. Using the scale comand this works, but the Z value is scaled as well. The thing is, I want to scale the X and Y only, not the Z.

 

So far the only way to do this is to create a block, scale it, then explode. This takes a lot of time that to me seems unnecessary.

 

So this is what I was thinking for a lisp routine that can do what I need.

 

Select a polyline (contours)

Scale the polyine to some factor.

Reset the Z value to the orginal value before scaling.

 

I hope this makes sense. Haha.

 

Anyone willing to tackle this?

[eldon]

Using the scale comand this works, but the Z value is scaled as well.

Anyone willing to tackle this?

 

If you scale the contours individually, then the Z value is not scaled.

 

Most people would probably scale the coordinates before they entered the data.

[BlackBox]

Look into vla-scaleEntity function.

[Bill_Myron]

eldon - The scale command scales the polyline uniformly. It applys the scale to all 3 axis. The data that was given to me was just the contour polylines. Therefore i can only use what was given.

 

Render man - Thanks for the start. Can this lisp be manipulated to only scale in the x and y directions and not the Z?

[Organic]

I have a great request. I need to scale some polyline contours from ground to grid coordinates.

 

Scaling contours like that is not a good practice in my opinion.

 

So far the only way to do this is to create a block, scale it, then explode. This takes a lot of time that to me seems unnecessary.

 

If this works and you only need to do it one off then why not just do this?

[BlackBox]

Render man - Thanks for the start. Can this lisp be manipulated to only scale in the x and y directions and not the Z?

 

What results did you get in your code testing?

[eldon]

The scale command scales the polyline uniformly. It applys the scale to all 3 axis.

 

Only if you scale about 0,0. If you scale each individual contour polyline about its own endpoint, the Z value is unaltered.

[marko_ribar]

(defun c:scpl ( / pt elev bpt entpl scf )
 (setq pt (getpoint "\nPick base point in XY plane for scaling your pline : "))
 (setq entpl (car (entsel "\nPick pline you want to scale")))
 (setq elev (cdr (assoc 38 (entget entpl))))
 (setq bpt (list (car pt) (cadr pt) elev))
 (setq scf (getreal "\nInput scale factor with or without decimal precision : "))
 (vl-cmdf "_.scale" entpl "" bpt scf)
(princ)
)

 

M.R.

[BlackBox]

(defun c:scpl ( / pt elev bpt entpl scf )
 (setq pt (getpoint "\nPick base point in XY plane for scaling your pline : "))
 (setq entpl (car (entsel "\nPick pline you want to scale")))
 (setq elev (cdr (assoc 38 (entget entpl))))
 (setq bpt (list (car pt) (cadr pt) elev))
 (setq scf (getreal "\nInput scale factor with or without decimal precision : "))
 (vl-cmdf "_.scale" entpl "" bpt scf)
(princ)
)

 

M.R.

 

I hope the user doesn't miss...

[BlackBox]

Slight revision to Marko's code (hope you don't mind):

 

(defun c:SCPL  () (c:ScalePlines))
(defun c:ScalePlines  (/ *error* nomutt oldNomutt ss pt scale)
 (princ "\rSCALE MULTIPLE POLYLINES ")
 (vl-load-com)

 (defun *error*  (msg)
   (and oldNomutt (setvar 'nomutt oldNomutt))
   (if acDoc (vla-endundomark acDoc))
   (cond ((not msg))                                                   ; Normal exit
         ((member msg '("Function cancelled" "quit / exit abort")))    ; <esc> or (quit)
         ((princ (strcat "\n** Error: " msg " ** "))))                 ; Fatal error, display it
   (princ))

 (defun nomutt (arg)
   (cond (oldNomutt)
         ((setq oldNomutt (getvar 'nomutt))))
   (if arg
     (setvar 'nomutt 1)
     (setvar 'nomutt 0)))
 
 (prompt "\nSelect multiple polylines to scale: ")
 (if (and (nomutt T)
          (setq ss (ssget "_:L" '((0 . "LWPOLYLINE"))))
          (nomutt nil)
          (setq pt (getpoint "\nSpecify base point: "))
          (setq scale (getreal "\nEnter scale factor: ")))
   ((lambda (acDoc / elev)
      (vla-startundomark acDoc)
      (vlax-for x  (setq ss (vla-get-activeselectionset acDoc))
        (setq elev (vla-get-elevation x))
        (vla-scaleentity x (vlax-3d-point pt) scale)
        (vla-put-elevation x elev))
      (vla-delete ss)
      (setvar 'nomutt oldNomutt)
      (vla-endundomark acDoc))
     (vla-get-activedocument (vlax-get-acad-object)))
   (cond (pt (prompt "\n** Scale factor required ** "))
         (ss (prompt "\n** Base point required ** "))
         ((prompt "\n** Nothing selected ** "))))
 (princ))

Edited August 30, 2011 by BlackBox
Revised code to allow selectionset, limit to LW*

[Bill_Myron]

Only if you scale about 0,0. If you scale each individual contour polyline about its own endpoint, the Z value is unaltered.

 

Scaling needs to be done from 0,0. there is no other way to get from ground to grid coordinates.

 

 

Dink87522 - I agree that this is not the best practice. All I have to work with are contours so i have to adjust. The method of blocking > scaling > exploding is so time consuming. There are about 5000 polylines, and exploded there are around 300,000 lines. There is just not tenough memory to do it all at once, so I have to do it in small selections. very time consuming.

 

 

RenderMan - I tried your latest code. It stills cales the z value. This is what I ended up with everytime i tried anything.

 

marko_ribar - Thats the one!! It has worked!! Holy smokes that will save loads of time.

 

 

Now I wonder if it can be modified to select multple polylines at once.

[BlackBox]

RenderMan - I tried your latest code. It stills cales the z value. This is what I ended up with everytime i tried anything.

...

Now I wonder if it can be modified to select multple polylines at once.

 

Code revised - now you can make one, single selection set of all your contours, and the entire selection set will be scaled from the same (user specified) base point. All elevations will remain the same as they were to start.

 

HTH

[Bill_Myron]

That is amazing. That wouldve taken me years to figure out that code.

 

It works perfectly!! Does in seconds what takes me a whole day to do.

 

 

Thanks for all the help!

[BlackBox]

That is amazing. That wouldve taken me years to figure out that code.

 

It works perfectly!! Does in seconds what takes me a whole day to do.

 

 

Thanks for all the help!

 

I'm happy to help.

 

That's very kind of you to say; Cheers!

[alanjt]

Slight revision to Marko's code (hope you don't mind):

 

(defun c:SCPL  () (c:ScalePlines))
(defun c:ScalePlines  (/ *error* nomutt oldNomutt ss pt scale)
 (princ "\rSCALE MULTIPLE POLYLINES ")
 (vl-load-com)

 (defun *error*  (msg)
   (and oldNomutt (setvar 'nomutt oldNomutt))
   (if acDoc (vla-endundomark acDoc))
   (cond ((not msg))                                                   ; Normal exit
         ((member msg '("Function cancelled" "quit / exit abort")))    ; <esc> or (quit)
         ((princ (strcat "\n** Error: " msg " ** "))))                 ; Fatal error, display it
   (princ))

 (defun nomutt (arg)
   (cond (oldNomutt)
         ((setq oldNomutt (getvar 'nomutt))))
   (if arg
     (setvar 'nomutt 1)
     (setvar 'nomutt 0)))
 
 (prompt "\nSelect multiple polylines to scale: ")
 (if (and (nomutt T)
          (setq ss (ssget "_:L" '((0 . "*POLYLINE"))))
          (nomutt nil)
          (setq pt (getpoint "\nSpecify base point: "))
          (setq scale (getreal "\nEnter scale factor: ")))
   ((lambda (acDoc / elev)
      (vla-startundomark acDoc)
      (vlax-for x  (setq ss (vla-get-activeselectionset acDoc))
        (setq elev (vla-get-elevation x))
        (vla-scaleentity x (vlax-3d-point pt) scale)
        (vla-put-elevation x elev))
      (vla-delete ss)
      (setvar 'nomutt oldNomutt)
      (vla-endundomark acDoc))
     (vla-get-activedocument (vlax-get-acad-object)))
   (cond (pt (prompt "\n** Scale factor required ** "))
         (ss (prompt "\n** Base point required ** "))
         ((prompt "\n** Nothing selected ** "))))
 (princ))

You might want to limit this to LWPolylines, or retool it a bit.

[BlackBox]

You might want to limit this to LWPolylines, or retool it a bit.

 

Thanks Alan ; code revised.

[alanjt]

Thanks Alan ; code revised.

Bored...

 

(defun c:SLWP (/ *error* ss point elev)

 (defun *error* (msg)
   (and *AcadDoc* (vla-endundomark *AcadDoc*))
   (if (and msg (not (wcmatch (strcase msg) "*BREAK*,*CANCEL*,*QUIT*,")))
     (princ (strcat "\nError: " msg))
   )
 )

 (vla-startundomark
   (cond (*AcadDoc*)
         ((setq *AcadDoc* (vla-get-activedocument (vlax-get-acad-object))))
   )
 )

 (princ "\nSelect LWPolylines to scale: ")
 (if (and (setq ss (ssget "_:L" '((0 . "LWPOLYLINE"))))
          (setq point (getpoint "\nSpecify base point: "))
          (progn (initget 6)
                 (setq *SLWP:factor*
                        (cond ((getdist (strcat "\nSpecify scale factor"
                                                (if (numberp *SLWP:factor*)
                                                  (strcat " <" (rtos *SLWP:factor*) ">: ")
                                                  ": "
                                                )
                                        )
                               )
                              )
                              (*SLWP:factor*)
                        )
                 )
          )
     )
   (progn
     (setq point (vlax-3d-point (trans point 1 0)))
     (vlax-for x (setq ss (vla-get-activeselectionset *AcadDoc*))
       (setq elev (vla-get-elevation x))
       (vla-scaleentity x point *SLWP:factor*)
       (vla-put-elevation x elev)
     )
     (vla-delete ss)
   )
 )
 (*error* nil)
 (princ)
)

[BlackBox]

Bored...

 

Boredom... the 'real' mother of invention.

[ice3cold]

Hi guys, I am using AutoCAD LT 2022 and don't have civil 3D. My issue is that when I try to scale the contours it changes the elevation. I got the elevation from GIS. I tried creating a block and then exploding it, that didn't work. I tried xref it in & bind, that didn't work. How can I scale the contour polylines without changing the elevation data? 

I read the forum, but I got lost. Can someone show me step by step? 

[marko_ribar]

I don't quite know ab contours as "special" entity type, but since you're on AutoCAD LT, you could perhaps try manually this procedure to achieve something described in this topic :

1. use UCS command to align coordinate system to desired plane for which scale operation is to be performed 

UCS -> "Object" option or "E" - entity, or by picking 3 points that are not collinear (UCS -> 3p -> 1 click, 2 click, 3 click, or 1 coord. specification, 2, 3...)

2. use SCALE command and pick point in previously changed coordinate system explained in 1. and enter scale factor you want if you need it uniformly scaled contour...

 

* if you need non uniform scale, then try like OP originally stated, creating temporarily block with BLOCK command - retain geometry (contour) and setting insertion point as your scale base origin point... Then adjust X and Y scale factors by modifying 1.0 values from Properties panel (in Vanilla AutoCAD - ctrl+1...) - i.e. keep Z value unchanged (1.0), but nevertheless as your base point was in UCS aligned with reference contour (block) - elevation of block won't change in Z direction no matter you changed Z value from 1.0 to any other value... After this task in panel, or ordinary SCALE command applied to block (if you still need X and Y fastors uniform and not different), you simply EXPLODE block with EXPLODE command and perform purging block definition from memory that was temporarily established to manage task you wanted - command is PURGE -> "B"lock option -> Name of block (type previously named block that was needed for creating block) for ex. "{tmp}" -> for verification of names, use "No" as answer... And that's all - block would be erased from memory and contour entity should be scaled according to your needed situation...