[vtkusers] volume rendering and progress methods

[alext at win.tue.nl]

  Hi all,

  I've got a question on volume rendering in vtk 3.1. Suppose one wants to stop an
ongoing volume rendering process, e.g. because one sees that the rendering
takes too long and/or the results are not as expected. I thought I could use
the interface of vtkProcessObject (inherited by e.g. the volumem mappers) to
a) set a progress method and b) set the AbortExecutr flag in this method via
a user interface, for example. 

  However, I saw that the progress method was actually not even called
during the volume rendering! Browsing through the volume code, I couldn't
find any occurence of the progress method being called and/or the
AbortExecute flag being checked. Does this mean that the volume rendering
mappers are NOT implementing the interface declared by the vtkProcessObject?
I suspect so, since very few VTK objects really implement that interface. 
If this is so, my question to the VTK people would be: is it difficult to
modify e.g. the vtkVolumeRayCastMapper to make it aware of the AbortExecute
flag? Do you plan to do this in a further release?

  Thanks for any hints on this,

  Alex Telea

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 Dr. Alexandru C. Telea      | Technische Universiteit Eindhoven
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