[Paraview] Multipiece Structured Dataset questions

[Erik Wilson]

Hello all,

I am attempting to develop a Paraview plugin to read in parallel a 
multipiece structured dataset through a custom I/O library. Since our 
data is already broken up into pieces it would be nice to use a grid 
type which has a DATA_EXTENT_TYPE of VTK_PIECES_EXTENT, otherwise when 
using VTK_3D_EXTENT extra code will need to be created to calculate and 
subtract sub-extents such as seen in vtkXMLPStructuredDataReader. There 
are three different options I am considering for developing this reader:

1) Use an Unstructured Grid

Simply translate our structured grid into a vtkUnstructuredGrid using 
Hexahedron cells. Will unstructured grids be as efficient as structured 
grids for operations such as cut planes and streamlines, or are there 
any efficiency disadvantages to using unstructured grids in general?

2) Subclass Structured Grid

Create a subclass of vtkStructuredGrid which uses has a DATA_EXTENT_TYPE 
of VTK_PIECES_EXTENT. Is this even feasible, or any other issues?

3) Use a Structured Grid

Just write the code to calculate and subtract 3d sub-extents, better 
than above options?


Any feedback or advice is greatly appreciated.

Thanks,
  -Erik