[Paraview] CleantoGrid tolerance parameter for merging points

[Sven Buijssen]

Hi Patrick,

Patrick Brockmann schrieb am 26.04.2015 um 19:17:
> Hi,
> 
> I like to see some points of an untsructured grid be merged ?
> Some points have coordinates equal to 1E-14, others 0.
> 
> When applying the CleantoGrid filter there is no entries 
> to specify a tolerance parameter. 

Internally, the filter relies since 2005 on vtkMergePoints which merges
points with coinciding coordinates. There is no room for a tolerance
parameter in that class. Previously, vtkPointLocator was used which
allowed to specify a tolerance.

> Am I missing something or the only way to do this today is to 
> apply a Calculator filter before with some new coordinates results as:
> ceil(coordsX*1000)/1000*iHat + ceil(coordsY*1000)/1000*jHat + ceil(coordsZ*1000)/1000*kHat
> It works but I would have prefered this kind of setting available from
> the CleantoGrid filter.
> 
> I have digged a similar question in 2007 
> http://www.paraview.org/pipermail/paraview/2007-May/004914.html
> 
> Let me know if I should put a request on this missing feature 
> on the paraview bug tracker or just live with it.

A few years back when I faced this challenge myself for the first time,
I wrote a small plugin subclassing vtkCleanUnstructuredGrid that uses
vtkPointLocator internally and allows to specify a tolerance parameter.
Let me know if you are interested.

Sven