[vtkusers] FieldData to PointData

Tue Jul 2 14:47:39 EDT 2002

A few comments:

1. I ran the script you included (I had to replace the input
of vtkRearrangeField with the output of the reader since there
is no do2ds). The output contains a scalars field which has
values of 0.328119. I can then read the file and color the
polygons it with these scalars.

2. The updates are not necessary. You can replace the last
update (write) with Write 

3. I don't understand why you are putting the array(s) in
the "general" field data. That is for data which is not normally
associated with geometry. You can instead add the array(s)
to the point data (or cell data). For example:

# vtk DataFile Version 3.0
vtk output
ASCII
DATASET POLYDATA

POINTS 12 float
-0.552786 -1.7013 -0.894427 -1.44721 -1.05146 0.894427 -1.78885 0
-0.894427 
0.552786 -1.7013 0.894427 1.78885 0 0.894427 1.44721 -1.05146 -0.894427 
0 0 -2 -0.552786 1.7013 -0.894427 1.44721 1.05146 -0.894427 
0.552786 1.7013 0.894427 0 0 2 -1.44721 1.05146 0.894427 

POLYGONS 20 80
3 0 1 2 
3 3 1 0 
3 5 3 0 
3 8 4 5 
3 4 3 5 
3 8 6 7 
3 7 6 2 
3 2 6 0 
3 0 6 5 
3 5 6 8 
3 9 10 4 
3 11 10 9 
3 1 10 11 
3 3 10 1 
3 4 10 3 
3 9 4 8 
3 7 9 8 
3 11 9 7 
3 2 11 7 
3 1 11 2 

CELL_DATA 20

POINT_DATA 12
FIELD Arrays 1
GaussCurvature 1 12 float
0.328119 0.328119 0.328119 0.328119 0.328119 0.328119 0.328119 0.328119
0.328119
0.328119 0.328119 0.328119 

You can get rid of the vtkRearrangeFields if you do it this way. Of
course, you can always do this:

# vtk DataFile Version 3.0
vtk output
ASCII
DATASET POLYDATA

POINTS 12 float
-0.552786 -1.7013 -0.894427 -1.44721 -1.05146 0.894427 -1.78885 0
-0.894427 
0.552786 -1.7013 0.894427 1.78885 0 0.894427 1.44721 -1.05146 -0.894427 
0 0 -2 -0.552786 1.7013 -0.894427 1.44721 1.05146 -0.894427 
0.552786 1.7013 0.894427 0 0 2 -1.44721 1.05146 0.894427 

POLYGONS 20 80
3 0 1 2 
3 3 1 0 
3 5 3 0 
3 8 4 5 
3 4 3 5 
3 8 6 7 
3 7 6 2 
3 2 6 0 
3 0 6 5 
3 5 6 8 
3 9 10 4 
3 11 10 9 
3 1 10 11 
3 3 10 1 
3 4 10 3 
3 9 4 8 
3 7 9 8 
3 11 9 7 
3 2 11 7 
3 1 11 2 

CELL_DATA 20

POINT_DATA 12
SCALARS GaussCurvature float
LOOKUP_TABLE default
0.328119 0.328119 0.328119 0.328119 0.328119 0.328119 0.328119 0.328119
0.328119 0.328119 0.328119 0.328119 

and get rid of vtkAssignAttribute as well. vtkAssignAttribute is most
commonly used when you have multiple arrays and you want to change which
one is currently marked as an attribute (scalars, vectors etc.)
You can also find some information on
http://public.kitware.com/cgi-bin/vtkfaq?req=show&file=faq06.009.htp

-Berk

On Tue, 2002-07-02 at 14:02, Philipp.Batchelor wrote:
> Hello,
> 
> maybe somebody can enlighten me, I don't seem to understand 
> how to the  FieldData is converted to PointData under vtk4.0.
> 
> I just want to render the field, here curvature. I used to store
> it as a 'vtkScalars', and that was it, but now, as I have to use
> FieldData->DataArray, I can't manage to get a PointData that can
> be rendered, or as in the code below, written to a file. The output
> file contains only the geometry.
> 
> Ph.
> 
> ----------------------------------------------------
> set scalar "GaussCurvature"
> 
> vtkDataSetReader reader
> reader SetFileName "icosaK.vtk"
> reader SetFieldDataName "Curvatures" 
> #necessary?
> reader Update
> 
> vtkRearrangeFields rf
> rf SetInput [do2ds GetOutput]
> rf AddOperation COPY $scalar DATA_OBJECT POINT_DATA
> rf Update
> 
> vtkAssignAttribute aa
> aa SetInput [rf GetOutput]
> aa Assign $scalar SCALARS POINT_DATA
> aa Update
> 
> vtkPolyDataWriter wr
> wr SetInput [aa GetOutput]
> wr SetFileName "tmp.pd.vtk"
> wr Update 
> ----------------------------------------------------
> 
> My example input data file is:
> 
> ----------------------------------------------------
> # vtk DataFile Version 3.0
> vtk output
> ASCII
> DATASET POLYDATA
> FIELD Curvatures 1
> GaussCurvature 1 12 float
> 0.328119 0.328119 0.328119 0.328119 0.328119 0.328119 0.328119 0.328119 0.328119
>  
> 0.328119 0.328119 0.328119 
> POINTS 12 float
> -0.552786 -1.7013 -0.894427 -1.44721 -1.05146 0.894427 -1.78885 0 -0.894427 
> 0.552786 -1.7013 0.894427 1.78885 0 0.894427 1.44721 -1.05146 -0.894427 
> 0 0 -2 -0.552786 1.7013 -0.894427 1.44721 1.05146 -0.894427 
> 0.552786 1.7013 0.894427 0 0 2 -1.44721 1.05146 0.894427 
> 
> POLYGONS 20 80
> 3 0 1 2 
> 3 3 1 0 
> 3 5 3 0 
> 3 8 4 5 
> 3 4 3 5 
> 3 8 6 7 
> 3 7 6 2 
> 3 2 6 0 
> 3 0 6 5 
> 3 5 6 8 
> 3 9 10 4 
> 3 11 10 9 
> 3 1 10 11 
> 3 3 10 1 
> 3 4 10 3 
> 3 9 4 8 
> 3 7 9 8 
> 3 11 9 7 
> 3 2 11 7 
> 3 1 11 2 
> 
> CELL_DATA 20
> POINT_DATA 12
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