[vtkusers] Volume Rendering problem

[Naoko Takaya]

To all vtkusers,

Howdy!!

I have a pblm with Volume Rendering. 
I use ;

vtkSrutcturedPoints
vtkPiecewiseFunction
vtkVolumeProperty
vtkVolumeRayCastCompositeFunction
vtkVolumeRayMapper
vtkVolume

When I see the result, it looks OK, but when turning it around
and having a closer look, the shape changes every time
I rotate. Why is this?
Some kind of planes and lines appear and not the solid shape.

Also, I don't exactly understand what "AddSegment" ( member of 
vtkPiecewiseFuntion ) does to the shape. 
I read the manual and said that it adds line segment to the
function and removes the points between the specified points.
But why use this when setting the color and opacity to the volume?

This might be a simple question but I hope you would help me.
Any help would very much be appreciated!!

Thank you in advance!!

PS 
   Just in case, I attached my pgm with.

********************************************************
*                Naoko Takaya                               *
*                                                                    *
*       e-mail: takaya at cv.cs.ritsumei.ac.jp         *
*                                                                    *
*********************************************************
-------------- next part --------------
A non-text attachment was scrubbed...
Name: volume.cxx
Type: application/octet-stream
Size: 6448 bytes
Desc: not available
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20000922/e3ee7403/attachment.obj>