[vtkusers] Question about intersections lines and vtkVolume (for raycasting)

[Robert Leśnik]

How to find intersection between line and vtkVolume (or general vtkProp) in
VTK? I need this information to check if the particular light source is
visible from particular volume in the scene. If the light source is visible
I have to send ray from this light to the particular voxel in checked volume
and sample this ray to compute the attenuation light intensity. At the voxel
I use this attenuated ligt intensity and angle between ray from light and
light from observer to compute color that will be acumulated in ray casting
process.
I'm interested for any information and suggestion, because I have to
implement lightning model for gaseous phenomena (like fog, smoke, clouds)
but I don't feel very familiar about it.
I excuse for my pure English and thanks for future help.
--
Robert