[vtkusers] Oriented Hexahedrons and Local Coordinate System

[Iman Khalaji]

Dear all,

I have been dealing with a problem in utilizing vtkTransform for the past
week. I am trying to develop a class to define bounding box for bent tubes.
Knowing that bent tubes are not aligned with global Coordinate system, I can
not use vtkBoundingBox at all, since the whole bound will be defined with
respect to global coordinate system. On the other hand, other classes like
vtkOBBTree can be used and by considering covariance matrix of all cells,
the tightest-fitting OBB (Oriented Bounding Box) may be extracted. However,
this does not suit my need either. To be precise, I do not want a rigid
bounding box with 90 degree angles at corners. I just want some hexahedrons
attached to each other which follow the whole path of the tube, provided
that twisting in path of hexahedrons is not accetptable.

Now, I am wondering if there is any class in vtk to do that? or can you
please let me know if coordinate system transformation is possible in vtk (I
have a solution in my mind regarding rotation of coordinate system at each
section and defining bounding rectangle at that section, but without
rotation around Z-axis)? I do not want to use actors and their
transformation, but I am seeking for any user defined local coordinate
system through which I can extract geometry of my PolyData in that new
coordinate system.

Thanks for your help in advance,

Iman Khalaji
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