[vtkusers] picking a voxel in a MIP volume

[Mark Wyszomierski]

Hi Ahmed,

Thanks for the ideas. For #2, wouldn't I cast a ray parallel to the
view (not perpendicular?). Everything else makes sense to me - just
need to figure out how to do it with VTK!!!

Thanks,
Mark

On 2/1/07, ahmed saad <ahmedalysaad2004 at yahoo.com> wrote:
>
> Hi,
>     I think I solved this problem before.
> Some Hints:
> 1) take the nearest point on the bounding box around the volume rendered
> object (vtkCellPicker)
> 2) shot a ray from this point perpendicular to the view direction.
> 3) get the intersection points along this ray to the volume data.
> 4) get the location (x,y,z) for the maximum intensity point(s).
> 5) if you have more than one point with maximum intensity. Choose the
> nearest one with respect to the viewer.
>
> Best regards,
> Ahmed Saad
>
>
> ----- Original Message ----
> From: Mark Wyszomierski <markww at gmail.com>
> To: David E DeMarle <dave.demarle at kitware.com>
> Cc: vtkusers at public.kitware.com
> Sent: Thursday, February 1, 2007 6:52:54 AM
> Subject: Re: [vtkusers] picking a voxel in a MIP volume
>
> hmm ok looks like i have to hack into the mapper then,
>
> thanks,
> mark
>
> On 1/31/07, David E DeMarle <dave.demarle at kitware.com> wrote:
> > I do not believe there is anything built in to do that. vtkCellPicker
> > will obtain the closest cell along the ray for that pixel (the one on
> > the near face) not the one that has the maximum value that you see
> > there.
> >
> > Dave DeMarle
> >
> >
> > On 1/31/07, Mark Wyszomierski <markww at gmail.com> wrote:
> > > Hi,
> > >
> > > I'm doing a MIP rendering. Is there a way to 'pick' a voxel in the
> > > rendered volume? I was thinking that the user could click a voxel in
> > > the MIP volume, then I could display the picked voxel's x,y,z
> > > location. Is this possible?
> > >
> > > Thanks,
> > > Mark
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