[vtkusers] how to get pixel coordinates of iso-surface

[Sean McInerney]

Hi,

  The vtkVolumeRayCastIsosurfaceFunction in conjunction with a
RayCastMapper does *NOT* generate triangles (as far as I know). It is a
form of volume rendering that terminates ray traversal upon encountering
the specified isovalue (800). By subclassing, you *may* be able to
access the ray caster data in order to determine the terminal
coordinate. Generating a PolyData isosurface via vtkContourFilter (or
others), however, should give you what you need (with a lot less effort).

-Sean

diaoxianfen wrote:
> I use the ray casting volume rendering to visualize image datas.The procedure as follows,
> vtkVolumeRayCastIsosurfaceFunction *isosurfaceFunction = 
>     vtkVolumeRayCastIsosurfaceFunction::New();
>   isosurfaceFunction->SetIsoValue(800);
>  raycastMapper->SetVolumeRayCastFunction( isosurfaceFunction ); 
> Every thing is Ok.
> Now I want to get the pixel coordinates of the isosurface of 800 gray value.I know that the isosurface
> is connected by triangles,how can I get the pixel coordinates or nearby coordinates corresponding to 
> the isosurface?
> thanks a lot!
>