[Paraview] holes in distributed polydata
burlen
burlen.loring at gmail.com
Thu Jan 14 12:04:35 EST 2010
Ken,
Here is a dataset that I am able to reproduce with:
http://nashi-submaster.ucsd.edu/movies/PV/holes.tar.gz
run with 96 procs. Set the view to +y. If the long holes aren't
appearing in your view I found that smaller holes can show up by
rotating the plane in small increments about either the x or z axis.
These ones are pretty small so you have to look closely.
Burlen
Moreland, Kenneth wrote:
> Burlen,
>
> Is there any possible way you can send me some data or replicate the
> problem with something like the Mandelbrot source? So far I have not
> been able to replicate it exactly.
>
> -Ken
>
>
> On 1/5/10 2:34 PM, "burlen" <burlen.loring at gmail.com> wrote:
>
> Ken,
> Some bad news, this patch didn't solve the problem, the holes returned
> on my first run.
> Burlen
>
>
> Moreland, Kenneth wrote:
> > That was not intended to be a solution, but rather a diagnostic. My
> > guess is that there are precision errors in the rasterization
> when the
> > viewport is shifted. Could you restore vtkIceTRenderManager and try
> > the attached patch to IceT?
> >
> > -Ken
> >
> >
> > On 12/10/09 12:26 PM, "burlen" <burlen.loring at gmail.com> wrote:
> >
> > Hi Ken,
> >
> > it seems to have solved the problems. I say that with fingers
> > crossed, I
> > haven't seen holes any since your suggested changes, where before
> > I was
> > seeing them quite often, popping up from time to time.
> >
> > Burlen
> >
> > Moreland, Kenneth wrote:
> > > Hmm. It is possible that the “floating viewport” feature of IceT
> > could
> > > be causing troubles with precision. Could you try adding
> > >
> > > icetDisable(ICET_FLOATING_VIEWPORT);
> > >
> > >
> > > somewhere in the vtkIceTRenderManager::UpdateIceTContext()
> method and
> > > see if the problem goes away?
> > >
> > > -Ken
> > >
> > >
> > > On 12/7/09 10:11 AM, "burlen" <burlen.loring at gmail.com> wrote:
> > >
> > > Hi Ken,
> > > For that figure you mention I turned on "surface with edges" to
> > > show the
> > > cell size better. Sorry I can see how that could be confusing. But
> > > just
> > > to clarify, there aren't actually any holes in the surface.
> > >
> > > Here is another zoom in of the same area where "surface with
> > edges" is
> > > off and you can see that there are no holes.
> > > http://nashi-submaster.ucsd.edu/movies/PV/bug-zoom.png
> > >
> > > Now I also have hit a case where after running through D3 I got a
> > hole
> > > at the process boundary. this run had 80 processes, the surface
> shown
> > > has dimensions of 5.5 x 10 units with 1500 x 2727quads with side
> > > 0.0036
> > > units.
> > > http://nashi-submaster.ucsd.edu/movies/PV/bug-d3.png
> > >
> > > I am only seeing this with the small quads and in parallel at
> process
> > > boundaries.
> > >
> > > Burlen
> > >
> > >
> > > Moreland, Kenneth wrote:
> > > > Burlen,
> > > >
> > > > For the zoom in, you say there are no holes/lines, but in the
> > image I
> > > > see a grid of lines. It looks like you have a bunch of little
> quads
> > > > with spacing in between them. Is this the case? If so, then the
> > > “hole”
> > > > artifacts you see on the bottom of the screen are probably simply
> > > > aliasing artifacts. They are places where the pixel happens to
> > align
> > > > right where the gap is.
> > > >
> > > > I can’t think of an easy way around this (other than to
> modify your
> > > > data to remove the gaps, if that makes sense). Anti-aliasing
> > > > techniques such as oversampling or smoothing would probably
> fix the
> > > > problem, but they would also break the parallel rendering so
> > they are
> > > > no good.
> > > >
> > > > -Ken
> > > >
> > > >
> > > > On 12/5/09 12:18 AM, "burlen" <burlen.loring at gmail.com> wrote:
> > > >
> > > > its ugly but I get a lot better performance by splitting the
> > work up
> > > > dynamically with a small grain size. in the run shown below
> > there are
> > > > only 16 processes but there are a whole lot of process
> boundaries.
> > > >
> > > > I was able to reproduce it on a second system today.
> > > >
> > > > these holes are pretty non-deterministic in where they show up.
> > > moving
> > > > the camera they can show up in different places. Which makes
> > sense if
> > > > this is related to some parallel rendering/finite precision issue
> > > with
> > > > all those process boundaries. The small size of the quads are
> > also a
> > > > factor, because I didn't ever notice it before when using larger
> > > > quads.
> > > >
> > > > I saved the data as a legacy file and opening it on my desktop
> > > > there are
> > > > no issues, so its definitely a parallel only issue. Also running
> > > > through
> > > > D3 seems to fix it, but the issue may still be there because
> > with the
> > > > minimal number of process boundaries its much less likely to
> > get the
> > > > camera in just the right position.
> > > >
> > > > Berk Geveci wrote:
> > > > > Ouch. That's very distributed :-) Does the problem go away
> > when you
> > > > > decrease the number of partitions?
> > > > >
> > > > > On Thu, Dec 3, 2009 at 10:55 AM, burlen
> <burlen.loring at gmail.com>
> > > > wrote:
> > > > >
> > > > >> I'm seeing lines where the background shows through a surface
> > > > polydata of
> > > > >> quads. When I zoom into the region to investigate the
> holes are
> > > > gone. Moving
> > > > >> the image around the holes appear in different places. They
> > > > depend on camera
> > > > >> position. In this surface there are 2.5E6 quads. the area is
> > > > 10x16 units and
> > > > >> the number of quads is 1250x2000. each quad has 0.008
> units on a
> > > > side. I
> > > > >> hadn't seen the holes before going to this higher resolution.
> > > > It's likely
> > > > >> that the hole is near a process boundary, in my polydata
> filter
> > > > each process
> > > > >> adds his quads to his output polydata, in this run the
> quads are
> > > > distributed
> > > > >> in strips of 512 as needed.
> > > > >>
> > > > >> 3 holes/lines in bottom half of the image (black background
> > > > shows through):
> > > > >> http://nashi-submaster.ucsd.edu/movies/PV/bug.png
> > > > >>
> > > > >> zoom in no holes/lines:
> > > > >> http://nashi-submaster.ucsd.edu/movies/PV/bug-zoom-2.png
> > > > >>
> > > > >> process boundaries (from process id filter):
> > > > >> http://nashi-submaster.ucsd.edu/movies/PV/bug-procs.png
> > > > >>
> > > > >> Should PV be able to handle a polydata distributed like this?
> > > > >>
> > > > >>
> > > > >>
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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>
> > <http://www.cs.unm.edu/%7Ekmorel>
> > > <http://www.cs.unm.edu/%7Ekmorel> <http://www.cs.unm.edu/%7Ekmorel>
> > > >
> > >
> > >
> > >
> > >
> > >
> > > **** 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>
> > <http://www.cs.unm.edu/%7Ekmorel> <http://www.cs.unm.edu/%7Ekmorel>
> > >
> >
> >
> >
> >
> >
> > **** 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> <http://www.cs.unm.edu/%7Ekmorel>
> >
>
>
>
>
> **** 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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