[vtkusers] Polydata + translucent volume

[Hämäläinen Janne]

Hi all,

I'm rendering 3D volume using predefined vtkColorTransferFunction and scalar
opacity function, and trying to render a 3D cursor (vtkCursor3D) into the
same scene. Problem is that although the focal point of the cursor should be
inside the visible part of the volume, it is rendered so that it is appears
to be outside the volume, i.e., so that there is no translucent volume
hiding it ( the cursor is the closest object to camera from view points ).
I've understood that there could be sometimes problems in ordering polydata
if there is objects in scene that has opacity less than 1. I've tried to
order actors in the renderer as was suggested in the vtk handbook ( volume
first and cursor last )  and also tried vtkDepthSortPolyData ( although
didn't understand how it works ), but nothing has helped. If someone has
knowledge on what I should do, please let me know.

Cheers, Janne



--
Janne Hämäläinen
Research Assistant
Helsinki University Central Hospital 
X-ray Department				

email   janne.hamalainen at hus.fi