Autolisp and getting ALTITUDE value

Hi all,

I need to read the value of "altitude" from the properties of
a polyline, in Autodesk Land Desktop 2005.

Does anyone know the command's needed to do this?

regards
Dom

 

Hi,

There are no commands of which I'm aware to publish this data.

You can get the information with the [Terrain][3D polylines][edit 3D
polyline] command.

With VBA you can get the polyline coordinates. You can extract the data and
format it any way you like.

Extract of help file below:

--


Laurie Comerford
CADApps
www.cadapps.com.au

Sub Example_Coordinates()
' This example creates a polyline. It then uses the Coordinates
' property to return all the coordinates in the polyline. It then
' resets one of the vertices using the Coordinates property.

Dim plineObj As AcadPolyline

' Create Polyline
Dim points(5) As Double
points(0) = 3: points(1) = 7: points(2) = 0
points(3) = 9: points(4) = 2: points(5) = 0
Set plineObj = ThisDrawing.ModelSpace.AddPolyline(points)
ThisDrawing.Regen True

' Return all the coordinates of the polyline
Dim retCoord As Variant
retCoord = plineObj.Coordinates

' Display current coordinates for the first vertex
MsgBox "The current coordinates of the second vertex are: " & points(3)
& ", " & points(4) & ", " & points(5), vbInformation, "Coordinates Example"

' Modify the coordinate of the second vertex to (5,5,0). Note that in
' case of a lightweight Polyline, indices will be different because the
points are 2D only.
points(3) = 5
points(4) = 5
points(5) = 0
plineObj.Coordinates = points

' Update display
ThisDrawing.Regen True

MsgBox "The new coordinates have been set to " & points(3) & ", " &
points(4) & ", " & points(5), vbInformation, "Coordinates Example"
End Sub
--


Laurie Comerford
CADApps
www.cadapps.com.au

 

Hi Dom

In addition to Laurie's VBA sample, the counterpart in LISP:

Code:

(defun C:GetPlineCoords ( / CurEnt CurObj ObjNme RetLst TmpLst)
(vl-load-com)
(setq CurEnt (entsel "\nSelect a Polyline: "))
(if CurEnt
(progn
(setq CurObj (vlax-ename->vla-object (car CurEnt))
ObjNme (vla-get-ObjectName CurObj)
)
(cond
((eq ObjNme "AcDbPolyline")		;LwPolyline
(setq TmpLst (vlax-get CurObj 'Coordinates))
(while
(setq RetLst (cons
(mapcar '(lambda (l) (nth l TmpLst)) '(0 1))
RetLst		;2D points
)
TmpLst (cddr TmpLst)
)
)
)
((wcmatch ObjNme "AcDb*Polyline")	;Old/3DPolyline
(setq TmpLst (vlax-get CurObj 'Coordinates))
(while
(setq RetLst (cons
(mapcar '(lambda (l) (nth l TmpLst)) '(0 1 2))
RetLst		;3D points
)
TmpLst (cdddr TmpLst)
)
)
)
((princ "selected object is not a Polyline. "))
)
)
)
(reverse RetLst)
)

Cheers

 

Hey,

Thanks for your quick responces! I have no experience with
VBA, had a go but couldn't get it running. I have used LISP
some, and have been able to get the X and Y co-ordinates,
before, using something similar. But I am needing to get the Altitude.

I can change it manualy, by selecting the polyline, then right
clicking, then properties. But I need to do it on lot's, so would
like a script to save time.

Is there something like:
(setq TmpLst (vlax-get CurObj 'Coordinates))

except using 'Altitude, as using 'Coordinates only gives me
the X and Y values, not the altitude. If I have understood correctly.

regards
Dom

 

Hi Dom

I'm not familiar with Autodesk Land Desktop...

My function returns a point list. A LwPolyline has no z coordinates,
old style Polylines and 3DPolylines have z coordinates.

Cheers

 

try looking at the "Elevation" property
(setq TmpElev (vlax-get CurObj 'Elevation))

 

sorry,
I assumed he was talking about lwpolylines "representing contours" of fixed
elevation
rather than 3d polylines
It's been a while since I worked in civil and back then contours were
represented (in plan view) by successive polylines - each at it's own
elevation - or at least labeled as an elevation -