[vtkusers] I need to get the X, Y, Z coordinates of a point in a vtkPolyData

Jérôme jerome.velut at gmail.com
Mon Oct 26 09:31:44 EDT 2009


In your code, you defined contour as the vtkContourFilter, not a polydata.
vtkContourFilter is a subclass of vtkAlgorithm that does not have a
GetPoints( ) function. You should take a look to VTK online documentation to
see what you can access from a class.
Basically, a subclass of vtkAlgorithm allows you to access input/ouput that
could be vtkPointSet
>From vtkPointSet (such as vtkPolyData, your interest...), you can acces
geometry through GetPoints( ) or topology through GetLines( ), GetVerts(),
GetPolys( ),...

In your case (from what I read  in your code), contour is a vtkAlgorithm. It
cannot be its own output in the same time.

I hope that helps

Jerome

2009/10/26 Alessandro Artusi <artusialessandro4 at googlemail.com>

> Dear Bill thanks a lot but it does not work I have still the same Attribute
> error.
>
> I repeat contour is where i store the output of teh vtkContourFilter(), may
> be it does not inerithance the GetPoints().....
>
> Any other suggestion?
>
> The vtkContourFilter has not any
>
> On Mon, Oct 26, 2009 at 2:44 PM, Bill Lorensen <bill.lorensen at gmail.com>wrote:
>
>> You must do
>> contour.Update()
>>
>> before accessing the points.
>>
>> On Mon, Oct 26, 2009 at 8:26 AM, Alessandro Artusi
>> <artusialessandro4 at googlemail.com> wrote:
>> > Thanks a lot Jerome,
>> >
>> > I get an errore:
>> >
>> > AttributeError GetPoints.
>> >
>> > May be I am doing something wrong; what i  am doing is the following:
>> >
>> > contour = vtk.vtkContourFilter()
>> > contour.SetInput(grid) #grid is rectilineargrid()
>> > contour.ComputeNormalOn()
>> > contour.SetValue(0, 95) #my isovalue
>> >
>> > in contour i should have my polyData right?
>> >
>> > when i do what you suggested:
>> >
>> > contour.GetPoints( ).GetPoint( pointId, coord )
>> >
>> > I got the error.
>> >
>> > Any suggestion?
>> >
>> > Thanks again,
>> > Alessandro.
>> >
>> >
>> > On Mon, Oct 26, 2009 at 1:11 PM, Jérôme <jerome.velut at gmail.com> wrote:
>> >>
>> >> Hi,
>> >> vtkPolyData is a vtkPointSet : you can access points coordinates
>> through
>> >>
>> >> polydata->GetPoints( )->GetPoint( pointId, coord )
>> >>
>> >> where polydata is your... polydata, pointId is the point Id you want to
>> >> get (from 0 to NumberOfPoints - 1) and coord is double coord[3] filled
>> by
>> >> the point coordinate.
>> >>
>> >> HTH
>> >> Jerome
>> >>
>> >> 2009/10/26 Alessandro Artusi <artusialessandro4 at googlemail.com>
>> >>>
>> >>> Dear All,
>> >>>
>> >>> I have a vtkPolyData from the vtkContourFilter and I need to get the
>> >>> X,Y,Z coordinates of each point in the PolyData. This because I need
>> to
>> >>> convert them.
>> >>> How can i get this info?
>> >>>
>> >>> Thanks a lot for teh help,
>> >>> Alessandro.
>> >>>
>> >>>
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