[vtkusers] problem with GetNumberOfPoints () and GetNumberOfCells ()

[Will Schroeder]

Hi Marco-

You've got to make sure the pipeline Updates() before asking for the number 
of points and/or cells. Just connecting filters together doesn't make it 
update. An Update() occurs automatically when you render; or if you are not 
rendering, you can manually invoke Update() on the end of the pipeline. 
Also, turn DebugOn() on one or more filters to track its execution.

Also,

>// type PolyData
>   vtkPolyData *polydatatemp = vtkPolyData::New();
>     polydatatemp = skinDecimate->GetOutput() ;

is a memory leak. GetOutput() returns its output, which overwrites the 
pointer to the data you just created. Do instead:

skinDecimate->DebugOn();
skinDecimate->Update();
vtkPolyData *polydatatemp = skinDecimate->GetOutput();

then ask for numbers of points and cells.

Will


At 12:43 AM 2/22/2002 +0100, Marco Kassner wrote:
>Hello.
>
>This is my first mail to the group.
>I develop a program which reads voxel data and calculates Spinmaps.
>Representing the data works easily but I have a problem to access the
>PolyData.
>I receive the result null for the function GetNumberOfPoints () and
>GetNumberOfCells ().

William J. Schroeder, Ph.D
Kitware, Inc.
469 Clifton Corporate Parkway
Clifton Park, NY 12065
will.schroeder at kitware.com
1-518-371-3971 x102
1-518-371-3971 (fax)