[vtkusers] Problem with vtkPolyDataToImageStencil in 5.8

[David Gobbi]

The contours must be polylines, not polygons, or it won't work.

On Tue, Mar 6, 2012 at 6:29 AM, Jothybasu Selvaraj <jothybasu at gmail.com> wrote:
> Yes, I have one contour for each z slice as a vtkPolyData. I will try
> removing that.
>
> Thanks
>
>
> On Tue, Mar 6, 2012 at 1:26 PM, David Gobbi <david.gobbi at gmail.com> wrote:
>>
>> Do you have one contour for each Z slice?  If so, then try removing
>> the Extrude filter from your pipeline.
>>
>>
>> On Tue, Mar 6, 2012 at 2:51 AM, Jothybasu Selvaraj <jothybasu at gmail.com>
>> wrote:
>> > Another point here,
>> >
>> > I am creating a vtkPolyData for each contour and then adding it to the
>> > vtkAppendPolydataFilter, then the output of vtkAppenPolydataFilter is
>> > set as
>> > input to vtkPolydataToImageStencil.
>> >
>> > Could this make any difference?
>> >
>> > Thanks
>> >
>> > Jothy
>> >
>> >
>> > On Mon, Mar 5, 2012 at 7:49 PM, Jothybasu Selvaraj <jothybasu at gmail.com>
>> > wrote:
>> >>
>> >> No, it doesn't fix the problem.
>> >>
>> >> But it seems to work fine for contours with z-spacing in steps of 1mm.
>> >>
>> >> It is working well for a dataset with 3mm spacing but fails for 2.5 mm.
>> >>
>> >> Maybe I need to test it thoroughly. Can I use those cxx and .h from 5.6
>> >> in
>> >> 5.8, that would be a easy workaround.
>> >>
>> >> Thanks
>> >>
>> >> Jothy
>> >>
>> >>
>> >> On Mon, Mar 5, 2012 at 4:01 PM, David Gobbi <david.gobbi at gmail.com>
>> >> wrote:
>> >>>
>> >>> Hi Jothy,
>> >>>
>> >>> It underwent significant changes, but the only change I can think
>> >>> of that might have affected your pipeline is the way that it does
>> >>> rounding, it used to use a Floor() method that provided a small
>> >>> tolerance even if you did SetTolerance(0).  Try calling
>> >>> SetTolerance(1e-6) on your PolyDataToImageStencil object, it
>> >>> might help.
>> >>>
>> >>>  - David
>> >>>
>> >>> On Mon, Mar 5, 2012 at 3:17 AM, Jothybasu Selvaraj
>> >>> <jothybasu at gmail.com>
>> >>> wrote:
>> >>> > Hi all,
>> >>> >
>> >>> > I was able to create a mesh using the following pipeline in 5.6 and
>> >>> > it
>> >>> > worked well
>> >>> >
>> >>> >
>> >>> >
>> >>> > vtkPolyDataToImageStencil->vtkLinearExtrusionFilter->vtkImageStencil->vtkDiscreteMarchingCubes
>> >>> >
>> >>> > Now, I have updated vtk to 5.8 and I am getting gaps in the mesh
>> >>> > along
>> >>> > the z
>> >>> > axis. I am really puzzled, I have tried with different data sets as
>> >>> > well.
>> >>> >
>> >>> > I have read somewhere that vtkPolyDataToImageStencil had some
>> >>> > changes
>> >>> > in
>> >>> > 5.8, does it has anything to do with this problem, or am I doing
>> >>> > anything wrong?
>> >>> >
>> >>> > I have contours of constant z-spacing.
>> >>> >
>> >>> > Any hints?
>> >>> >
>> >>> > Thanks
>> >>> >
>> >>> > --
>> >>> > Jothy
>> >>
>> >>
>> >>
>> >>
>> >> --
>> >> Jothy
>> >>
>> >
>> >
>> >
>> > --
>> > Jothy
>> >
>
>
>
>
> --
> Jothy
>