[Paraview] holes in distributed polydata
burlen
burlen.loring at gmail.com
Tue Jan 19 15:21:19 EST 2010
In a quick check it looks to have made a difference. I will report back
if I see anything as I have a chance to use it more on the cluster.
Thanks Ken!
Burlen
Moreland, Kenneth wrote:
> I can’t find anything wrong other then there must be some sort of
> precision issue that is interfering with the decision of when to draw
> a polygon that is smaller than a pixel. I just checked in a change to
> IceT that prevents shifting around the projection matrix in
> single-display mode. That should fix the problem.
>
> -Ken
>
>
> On 1/15/10 11:07 AM, "burlen" <burlen.loring at gmail.com> wrote:
>
> Using the dataset below I can reproduce the issue on my workstation
> using 4 processes and both hardware and mesa rendering.
>
> burlen wrote:
> > 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>
> >> <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>
> >> <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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