[Paraview] Problem reading/using STRUCTURED_GRID data

[Moreland, Kenneth]

First, let me recommend that you update your version of ParaView (which you can download from www.paraview.org).  Version 2.4 was released several years ago and is no longer supported.

That said, I see that the behavior you describe also exists in the latest released version (3.2).  It looks like the data file is defining a lookup table with a domain from 0 to 1.  You can fix the problem by simply not defining a lookup table for the data in the file.  Change the line "LOOKUP_TABLE lut" to "LOOKUP_TABLE default" and the ParaView lookup table will be used as expected.  You can also delete the entire LOOKUP_TABLE section at the bottom of the file.

Why the lookup table defined in the file is scaling from 0 to 1 and how to get past that, I don't know.  Personally, I don't use this feature and don't recommend it to any ParaView users because it has dubious value and usually leads to confusing results (as you have just found).  If you really care about this feature, you should bring it up with the vtkusers list.

-Ken

> -----Original Message-----
> From: paraview-bounces at paraview.org [mailto:paraview-bounces at paraview.org]
> On Behalf Of Phil Goddard
> Sent: Sunday, August 17, 2008 11:38 PM
> To: paraview at paraview.org
> Subject: [Paraview] Problem reading/using STRUCTURED_GRID data
>
>
> I'm attempting to use Paraview for the first time, and trying to get a
> feel
> for it by reading in a simple sample data set.
> However the results are not as I expect and I'm wondering if someone could
> give me some idea of what I am doing wrong.
> I'm using version 2.4, release 4 from the CD that comes with the VTK Users
> Guide (VTK 5.0.4) on Windows 2000.
> My data file is appended below.
>
> From my understanding of my .vtk file I expect to see all points at z=0 as
> red, z=1 as green and z=2 as blue.
> What I actually see is the points at z=1 being blue (z=0 and z=2 are red
> and
> blue respectively).
>
> If I use a probe to look at the data, those at z=1 seem to have a value of
> 1
> as I expect.
>
> If I change the Representation to Surface then the sides of the cube have
> the colours
> 0<red<0.33
> 0.33<green<0.66
> 0.66<blue<2
>
> Also, if I display the Scalar Bar and set its Resolution property to 3
> then
> I get a Scalar Bar showing
> 0<blue<0.66<green<1.33<red<2.
> This is the reverse of the lookup table that I have read in.
>
> So several questions:
> 1. Why when viewed as points are those at z=1 not green?
> 2. Why when viewed as a Surface do I get the colors described above?
> 3. Why does the Scalar Bar have the colours reversed (from what I expect)?
>
> Much appreciated
> Phil.
>
>
> %%%%%%%%%%%% CUT HERE %%%%%%%%%%%%%%%%
> # vtk DataFile Version 2.0
> Test data for a cube in 3D space
> ASCII
>
> DATASET STRUCTURED_GRID
> DIMENSIONS 3 3 3
> POINTS 27 float
> 0 0 0
> 1 0 0
> 2 0 0
> 0 1 0
> 1 1 0
> 2 1 0
> 0 2 0
> 1 2 0
> 2 2 0
> 0 0 1
> 1 0 1
> 2 0 1
> 0 1 1
> 1 1 1
> 2 1 1
> 0 2 1
> 1 2 1
> 2 2 1
> 0 0 2
> 1 0 2
> 2 0 2
> 0 1 2
> 1 1 2
> 2 1 2
> 0 2 2
> 1 2 2
> 2 2 2
>
> POINT_DATA 27
> SCALARS CubeData float 1
> LOOKUP_TABLE lut
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 1.0
> 1.0
> 1.0
> 1.0
> 1.0
> 1.0
> 1.0
> 1.0
> 1.0
> 2.0
> 2.0
> 2.0
> 2.0
> 2.0
> 2.0
> 2.0
> 2.0
> 2.0
> LOOKUP_TABLE lut 3
> 1.0 0.0 0.0 1.0
> 0.0 1.0 0.0 1.0
> 0.0 0.0 1.0 1.0
> %%%%%%%%%%%% CUT HERE %%%%%%%%%%%%%%%%
>
>
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