[vtkusers] Observers & Volume Rendering

[Charles Boivin]

Hello all,

I would like to get some observers connected with volume rendering
modules to get an idea of how long a render will take.

For geometric modules, like getting an isosurface using
vtkContourFilter, I can just call
vtkContourFilter::AddObserver(vtkCommand::ProgressEvent, myObserver).
This works fine. I am having some problems finding the module I should
observe for volume rendering, however...

My instinct was to observer vtkVolumeRayCastMapper.. but this does not
seem to work. It does not seem to generate either a Start, End, or
Progress Event. Which module should I observer? The raycast function? Or
should it be the vtkLODProp3D that I am using?

Thank you in advance for your help... getting some progress info on the
raytracing is perhaps the most important of all, as these renders can be
quite time-consuming!

Charles Boivin