Invalid class: Heavy polylines

Are 2d (heavy) polylines going extinct? Is that why I get the following?
Just curious...

I'm picking a POLYLINE that's been converted from an LWPolyline to
Heavy, so it's now an AcDb2dPolyline. Here's what the assoc data looks
like when unclumped:

Command: get
Select object:
(-1 . <Entity name: 7efa6690>)
(0 . POLYLINE)
(330 . <Entity name: 7ef8e008>)
(5 . B652)
(100 . AcDbEntity)
(67 . 0)
(410 . Model)
(8 . HATCH-OL-BRICK)
(100 . AcDb2dPolyline)
(66 . 1)
(10 0.0 0.0 0.0)
(70 . 1)
(40 . 0.0)
(41 . 0.0)
(210 0.0 0.0 1.0)
(71 . 0)
(72 . 0)
(73 . 0)
(74 . 0)
(75 . 0)


Now pick the same polyline:

Command: (setq ep (entsel "\nPick entity: "))

Pick entity: (<Entity name: 7efa6690> (4639.94 4596.06 0.0))


Command: (setq vo (vlax-ename->vla-object (car ep )))
#<VLA-OBJECT IAcadLWPolyline 0ff856c4>

And dump it:

Command: (vlax-dump-object vo)
; IAcadLWPolyline: AutoCAD Lightweight Polyline Interface
; Property values:
; Application (RO) = #<VLA-OBJECT IAcadApplication 00b9b5e4>
; Area (RO) = AutoCAD.Application: Invalid class
; Closed = AutoCAD.Application: Invalid class
; ConstantWidth = AutoCAD.Application: Invalid class
; Coordinate = ...Indexed contents not shown...
; Coordinates = AutoCAD.Application: Invalid class
; Document (RO) = #<VLA-OBJECT IAcadDocument 01161740>
; Elevation = AutoCAD.Application: Invalid class
; Handle (RO) = "B652"
; HasExtensionDictionary (RO) = 0
; Hyperlinks (RO) = #<VLA-OBJECT IAcadHyperlinks 0ff76f14>
; Layer = "HATCH-OL-BRICK"
; Length (RO) = AutoCAD.Application: Invalid class
; Linetype = "BYLAYER"
; LinetypeGeneration = AutoCAD.Application: Invalid class
; LinetypeScale = 1.0
; Lineweight = -1
; Normal = AutoCAD.Application: Invalid class
; ObjectID (RO) = 2130339472
; ObjectName (RO) = "AcDb2dPolyline"
; OwnerID (RO) = 2130239496
; PlotStyleName = "ByLayer"
; Thickness = AutoCAD.Application: Invalid class
; TrueColor = #<VLA-OBJECT IAcadAcCmColor 0ff71bd0>
; Visible = -1

 

Randy,
I think you need to release the old vla-object before you
use vlax-ename->vla-object on the new object.
By converting the polyline without releasing the object,
the vla-object is still cast to the old object type (I think).

Close the drawing and open it again. All the problems
will probably go away.

 

Hi Doug,
Thanks! -

2) You're right -- closing and reopening the drawing fixed it, but

1) I don't see where the old object is ever touched by anything even
requiring (vl-load-com), much less any vlax- functions; my 'get' routine
uses only vanilla lisp functions. But I opened a new drawing, drew an
lwpoly, converted heavy, selected 'last', and got the correct result
this time, so...

 

In addition to making the variable local, I should get in the habit of
performing

(if vo (vlax-release-object vo))

at the end of these fns?

 

Randy,
Glad its working for you. Its really impossible
to guess what's causing your problems without
looking at your code, the command history, and
any reactors running.

At least you know now that AutoCAD still
supports the heavy polylines.

 

No reactors running; just simple straighforward etudes like the following - in general is a vlax- object 'attached' by vlax-ename->vla-object or by vlax-get-property such that it needs to be released?

; AL - Get Arclength property from an entity that has one.
(vl-load-com)
(defun c:al ( / ep vo)
(cond
( (not (setq ep (entsel "\nPick Arc: ")))
(princ "\nMissed. Try again. ")
)
( (not
(vlax-property-available-p
(setq vo (vlax-ename->vla-object (car ep ))) 'ArcLength
)
)
(princ "\nEntity is not an Arc. Try again. ")
)
( t
(princ
(strcat
"\nArcLength="
(rtos (vlax-get-property vo 'ArcLength) 2 2)
"ft."
)
)
)
)
(if vo (vlax-release-object vo)) ; this addition doesn't appear to do any harm at least...
(princ)
)