[vtkusers] How to use vtkCellDerivatives with unstructured grid image

[Seth Gilchrist]

Hi Dominik,
thanks for your reply, this makes sense and was along the lines of what I
have been trying.  Can you tell me how you arrived at 0, and 1 for the
fieldAssociation values?  Is that just the order of the  enumerator list
located at:

http://www.vtk.org/doc/nightly/html/classvtkDataObject.html#a54fdf8345a01c89e618feca3c10002b1

Thanks,
Seth





On Wed, Jun 15, 2011 at 3:12 PM, Dominik Szczerba <dominik at itis.ethz.ch>wrote:

> I never used the filter (in such cases I recommend custom filters) but
> may be able to clarify some confusion about SetInputArrayToProcess. It
> just explicitly tells the filter which array and of which type to take
> in case there are multiple ones:
>
>
> http://www.vtk.org/doc/nightly/html/classvtkAlgorithm.html#a6bea16e1329609dbccce0ff8d2367484
>
> Typical use:
>
> SetInputArrayToProcess(0,0,0,0,"PointScalar");
> SetInputArrayToProcess(0,0,0,1,"CellMarker");
>
> Good luck
> Dominik
>
>
> On Wed, Jun 15, 2011 at 8:25 PM, Seth Gilchrist <seth at mech.ubc.ca> wrote:
> > Hello,
> > Sorry to bump, but I'm still struggling with this and can't find any
> > good help in my books or online.  I have the "VTK Users Guide" and
> > "The Visualization Toolkit: An Object-Oriented Approach to 3-D
> > Graphics," but neither of them is any help in this case.
> >
> > Can anybody help with this question?  Examples, hints, whatever you
> > can do is really appreciated.
> >
> > Cheers,
> > Seth
> >
> > Previous message:
> > Hello,
> > I have the unstructured grid image printed at end of this email, with two
> > point data sets "Dispamcement" (vectors) and "Optimizer Value" (scalors).
>  I
> > want to use vtkCellDerivatives to calculate the strain tensors from the
> > "Displacement" point data.  I can't figure out how to input the data into
> > vtkCellDerivatives.  I have tried:
> >
> > vtkCellDerivatives  *dCalc = vtkCellDerivatives::New();
> > dCalc->
> > SetTensorModeToComputeStrain();
> > dCalc->SetInput( image->GetPointData()->GetArray("Displacement") );
> > dCalc->Update();
> >
> > and
> >
> > vtkCellDerivatives  *dCalc = vtkCellDerivatives::New();
> > dCalc->SetTensorModeToComputeStrain();
> > dCalc->SetInput(image);
> > dCalc->SetInputArrayToProcess( [uh...I get lost here, I've tried a lot of
> > things]  );
> > dCalc->Update();
> >
> > I either can't get it to compile, or the output of the filter is the same
> as
> > the input.
> >
> > Can anybody point me in the right direction?
> >
> > Thanks,
> > Seth
> >
> > The cells in the image are quadratic tets.
> >
> > image->Print( std::cout )...
> >
> > vtkUnstructuredGrid (0x10f1150)
> >  Debug: Off
> >  Modified Time: 268
> >  Reference Count: 1
> >  Registered Events: (none)
> >  Source: (none)
> >  Information: 0x10e6130
> >  Data Released: False
> >  Global Release Data: Off
> >  UpdateTime: 269
> >  Release Data: Off
> >  UpdateExtent: Not Initialized
> >  Update Number Of Pieces: 1
> >  Update Piece: 0
> >  Update Ghost Level: 0
> >  MaximumNumberOfPieces: 1
> >  RequestExactExtent: Off
> >   Field Data:
> >    Debug: Off
> >    Modified Time: 252
> >    Reference Count: 1
> >    Registered Events: (none)
> >    Number Of Arrays: 0
> >    Number Of Components: 0
> >    Number Of Tuples: 0
> >  Number Of Points: 81
> >  Number Of Cells: 30
> >  Cell Data:
> >    Debug: Off
> >    Modified Time: 259
> >    Reference Count: 1
> >    Registered Events: (none)
> >    Number Of Arrays: 0
> >    Number Of Components: 0
> >    Number Of Tuples: 0
> >    Copy Tuple Flags: ( 1 1 1 1 1 0 1 )
> >    Interpolate Flags: ( 1 1 1 1 1 0 0 )
> >    Pass Through Flags: ( 1 1 1 1 1 1 1 )
> >    Scalars: (none)
> >    Vectors: (none)
> >    Normals: (none)
> >    TCoords: (none)
> >    Tensors: (none)
> >    GlobalIds: (none)
> >    PedigreeIds: (none)
> >  Point Data:
> >    Debug: Off
> >    Modified Time: 268
> >    Reference Count: 1
> >    Registered Events: (none)
> >    Number Of Arrays: 2
> >    Array 0 name = Displacement
> >    Array 1 name = Optimizer Value
> >    Number Of Components: 4
> >    Number Of Tuples: 81
> >    Copy Tuple Flags: ( 1 1 1 1 1 0 1 )
> >    Interpolate Flags: ( 1 1 1 1 1 0 0 )
> >    Pass Through Flags: ( 1 1 1 1 1 1 1 )
> >    Scalars: (none)
> >    Vectors: (none)
> >    Normals: (none)
> >    TCoords: (none)
> >    Tensors: (none)
> >    GlobalIds: (none)
> >    PedigreeIds: (none)
> >  Bounds:
> >    Xmin,Xmax: (57.5, 67.3)
> >    Ymin,Ymax: (45.7, 56.7)
> >    Zmin,Zmax: (41.7, 59.1)
> >  Compute Time: 283
> >  Number Of Points: 81
> >  Point Coordinates: 0x10e7890
> >  Locator: 0
> >  Number Of Pieces: 1
> >  Piece: 0
> >  Ghost Level: 0
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