[Paraview] Error in MultiBlockPLOT3DReader

[Richard GRENON]

Hello,

I discovered Paraview 3.2.1 recently, Nice software.

I am using the MultibockPLOT3DReader for my data and I have found an 
error when reading Fortran Unformatted Plot3D files, that is reading 
with the options "Binary File", "Multi Grid" and "Has Byte Count" set 
on: when reading MultiGrid files with 5 grids, I have found that 
Paraview computed wrong min and max values of density, momentum 
components and stagnation energy. In particular, the min value of 
density was set to zero, athough I knew it should be 0.5857 for my data, 
and computing other Plot3d functions failed.

My Fortran Unformatted PLOT3D files were tested without problem in 
Fieldview, so I don't think they are corrupted. And also, I have 
verified with a C program that the true min and max values were not the 
values computed by Paraview. But all became OK in Paraview after I 
converted my data in pure Binary files without Byte Count, so the 
problem in Paraview is really when reading Fortran Unformatted PLOT3D 
files that require "Binary File", "Multi Grid" and "Has Byte Count" to 
be set on together.

I looked at the source and I have found that the MultiBlockPLOT3DReader 
skips the four leading "Byte Count" bytes before reading all density, 
momentum and stagnation energy values in a single record, but it does 
not skip again the trailing "Byte Count" bytes after reading the data 
record as it should do! That does not matter if you have a single grid 
file, but when you have several grids, data are shifted in the arrays 
each you read a new grid. The problems is only when reading the "q" file 
in the loop on i from 0 to numBlocks starting at line 943 in the file 
"vtkMultiBlockPLOT3DReader.cxx". I think that you should add 
"this->SkipByteCount(qFp)" at the end of the loop just after line 1059.

I hope that developers can check if I am right, and maybe include the 
corrected reader in a future Paraview release?

Best regards.

-- 
 Richard GRENON
 ONERA
 Departement d'Aerodynamique Appliquee - DAAP/ACI
 8 rue des Vertugadins
 92190 MEUDON - FRANCE
 phone : +33 1 46 73 42 17
 fax   : +33 1 46 73 41 46
 mailto:Richard.Grenon at onera.fr
 http://www.onera.fr