[Paraview] Disabling polygon offset (z-fighting prevention) in Paraview

Wed Jun 30 13:00:09 EDT 2010

It should be:

from libvtkRenderingPython import vtkMapper

This should work, but if it does not then you may need to set your
LD_LIBRARY_PATH to include the directory with the .so.

For Windows it would be:

   from vtkRenderingPython import vtkMapper

Pat

On Wed, Jun 30, 2010 at 12:53 PM, Paul Edwards <paul.m.edwards at gmail.com>wrote:

> I get the following error when calling "from libvtkRendering.so import
> vtkMapper":
>
>      ImportError: dynamic modules does not define init function
>
> Can anyone see what I am doing wrong?
>
> I'm on linux with an up-to-date development version.
>
> Thanks in advance,
> Paul
>
> PS I'm having problems with contour lines showing through the surface.
>  Commenting out the lines (199 & 200) in vtkProcessModule.cxx but this is
> for a user who has an existing version...
>
> On 30 October 2009 12:04, Utkarsh Ayachit <utkarsh.ayachit at kitware.com>wrote:
>
>> Oluminde,
>>
>> It makes sense to provide an option in the "Settings" dialog to
>> tweak/disable offsetting for resolving z-fighting. I've added a
>> feature request to the bug tracker:
>> http://paraview.org/Bug/view.php?id=9801
>>
>> To fix this without recompiling, here's a crazy hack to overcome this
>> issue in builtin mode (i.e. when not connected to server):
>> Before loading any datasets
>> * open python shell
>> * Run the following commands:
>>  > import os
>>  > if os.name == "posix":
>>  >      from libvtkRendering.so import vtkMapper
>>  > else:
>>  >      from vtkRenderingPython import vtkMapper
>>  > vtkMapper.SetResolveCoincidentTopologyToOff()
>>
>> If connected to a server, you can run the same python commands as part
>> of the python script for a programmable source or filter.
>>
>> Utkarsh
>>
>>
>> On Fri, Oct 30, 2009 at 6:48 AM, Utkarsh Ayachit
>> <utkarsh.ayachit at kitware.com> wrote:
>> > Ken,
>> >
>> > Offsetting the points/lines handles the cases when people try to
>> > render two overlapping datasets: one as surface and other as
>> > wireframe, and they don't necessarily want to show surface with edges
>> > (say they want scalar coloring for both surface and the wireframe). I
>> > believe Jean Favre has several such use cases.
>> >
>> > Utkarsh
>> >
>> > On Mon, Oct 26, 2009 at 1:18 PM, Moreland, Kenneth <kmorel at sandia.gov>
>> wrote:
>> >> Utkarsh,
>> >>
>> >> After reading this question from Olumide, I noticed that ParaView now
>> turns
>> >> on ZShift for lines and points (vtkProcessModule.cxx, 198-199).  I
>> don’t
>> >> know why this is.  This effect is turned off when drawing surface+edges
>> >> (vtkOpenGLCoincidentTopologyResolutionPainter.cxx, 56-58) because it
>> >> automatically switches to offsetting the polygons the polygons back
>> >> (vtkOpenGLRepresentationPainter.cxx, 79-85).  Should we remove those
>> two
>> >> lines from vtkProcessModule.cxx?
>> >>
>> >> -Ken
>> >>
>> >>
>> >> On 10/26/09 12:53 AM, "Olumide" <50295 at web.de> wrote:
>> >>
>> >> Hi -
>> >>
>> >> I use Paraview not for visualizing datasets, but for inspecting
>> >> polygonal meshes and the operations I perform on them. My work involves
>> >> computing various points and line segments on meshes, and I use
>> >> VTK/Paraview to see if the points and line segments are where they
>> ought
>> >> to be (if not, I conclude that there's a bug in my code and then
>> proceed
>> >> to hunt it down).
>> >>
>> >> <Digression>
>> >> Why I use VTK for this task: VTK is the the only publicly available 3d
>> >> graphics file format I'm aware of that explicitly supports and points,
>> >> lines, and meshes, and has a viewer for viewing these entities. Most
>> >> other 3d graphics file formats either support surfaces alone or have no
>> >> ready-made viewers.
>> >> </Digression>
>> >>
>> >> Lately however, upon closer inspection, I've noticed that many of the
>> >> points and line segments that I compute appear to hover above the mesh
>> >> they are computed from and never quite touch it, and points never seem
>> >> to lie on the line segments they are supposed to. For example, see:
>> >> http://i17.photobucket.com/albums/b52/videohead/SurfaceError.png
>> >> (note that the yellow line segment hover above the blue surface in the
>> >> horizon)
>> >>
>> >> After much experimentation, debugging and consultation, I now suspect
>> >> that this is caused by polygon offset in Paraview, designed to prevent
>> >> z-fighting. I would therefore like to know:
>> >>
>> >> (i.) if my suspicion is correct i.e. Paraview implement polygon offset
>> >> for preventing z-fighting in this case
>> >>
>> >> (ii.) if the above is true, how polygon offset can be disabled without
>> >> recompiling the source
>> >>
>> >> Thanks,
>> >>
>> >> - Olumide
>> >>
>> >> _______________________________________________
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>> >>
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>> >>
>> >>
>> >>
>> >>    ****      Kenneth Moreland
>> >>     ***      Sandia National Laboratories
>> >> ***********
>> >> *** *** ***  email: kmorel at sandia.gov
>> >> **  ***  **  phone: (505) 844-8919
>> >>     ***      web:   http://www.cs.unm.edu/~kmorel<http://www.cs.unm.edu/%7Ekmorel>
>> >>
>> >>
>> >
>> _______________________________________________
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>
>
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>
> Visit other Kitware open-source projects at
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>
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