[Paraview] Rendering bug?

[Scott, W Alan]

I believe Ken is correct.  I just offset wavelet2 by Z == 0.001, rebuilt the pipeline, and the problem goes away.

Alan 

> -----Original Message-----
> From: paraview-bounces at paraview.org 
> [mailto:paraview-bounces at paraview.org] On Behalf Of Sven Buijssen
> Sent: Wednesday, November 11, 2009 8:09 AM
> To: Moreland, Kenneth
> Cc: paraview at paraview.org
> Subject: Re: [Paraview] Rendering bug?
> 
> Hi Ken,
> 
> Thanks for the elaborate explanation. I'll think of something.
> 
> Sven
> 
> ----- Original Message -----
> From: "Moreland, Kenneth" <kmorel at sandia.gov>
> To: "Sven Buijssen" <sven.buijssen at tu-dortmund.de>, 
> "paraview at paraview.org"
> <paraview at paraview.org>
> Sent: 11/11/09 15:48:59
> Subject: [Paraview] Rendering bug?
> > I do not think that this is a rendering problem.  I think you have 
> > just fooled the filter that extracts the external faces of 
> the blocks 
> > (which is what is actually rendered).  Notice that when you arrange 
> > the overlapping meshes exactly as you are doing, that some of the 
> > faces are coincident.  In particular, the face that is missing is 
> > coincident.  Up to the point before you run clean to grid, 
> these faces 
> > are topologically distinct because they use an independent 
> (although 
> > coincident) set of points.  When you run clean to grid, 
> these coincident points are merged.
> >  When the points are merged, the cells from the two meshes 
> now share 
> > the same indexed points.  At this point, these faces are no longer 
> > topologically distinct.  The external faces filter notices 
> that these 
> > two faces use the same points and marks it as a neighbor 
> face (this is 
> > the definition of a neighbor face) and "correctly" removes it.
> > 
> > The problem is basically that when you append the data sets you are 
> > creating a non-manifold mesh.  To correct the problem, you 
> need some 
> > sort of filter that identifies coincident cells and removes 
> duplicates.
> >  I know of no such filter, so you will probably have to 
> write your own.
> > 
> > -Ken
> > 
> > 
> > On 11/11/09 7:33 AM, "Sven Buijssen" 
> <sven.buijssen at tu-dortmund.de> wrote:
> > 
> >     Hi,
> > 
> >     I've come across something that I consider a rendering bug, but
> >     before filing a
> >     bug report I'd like to discuss it first. Maybe it 
> sounds familiar.
> >     (I'm guess
> >     it's not related to the z-fighting issue discussed last week.)
> > 
> >     I have two volume grids consisting of hexaeder which partially
> >     overlap (wavelet
> >     sources for demonstration purposes in the attached *.pvsm file).
> >     After applying
> >     AppendDataSets and CleantoGrid filter it looks like the 
> resulting
> >     grid contains
> >     all points and cells except the cell at the 
> intersection of the two
> >     grids. See
> >     attached image.
> >     But the "missing" cell is actually there. Twice. It can 
> be confirmed
> >     by applying
> >     a ProgrammableFilter to add a cell array with cell numbers and
> >     applying a
> >     Threshold filter. Set both lower and upper threshold to 
> either 0 or
> >     30 to verify
> >     that the "missing" cell is still there. It simply not 
> rendered any more.
> > 
> >     It happens with PV 3.6.1 binary release and PV compiled from CVS
> >     HEAD. (The
> >     state file has been created with PV from CVS HEAD.)
> > 
> >     Any thoughts?
> > 
> >     Thanks
> >     Sven
> > 
> > 
> > 
> >    ****      Kenneth Moreland
> >     ***      Sandia National Laboratories
> > ***********
> > *** *** ***  email: kmorel at sandia.gov
> > **  ***  **  phone: (505) 844-8919
> >     ***      web:   http://www.cs.unm.edu/~kmorel
> > 
> 
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