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<TITLE>Re: [Paraview] holes in distributed polydata</TITLE>
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<FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>Burlen,<BR>
<BR>
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.<BR>
<BR>
-Ken<BR>
<BR>
<BR>
On 1/5/10 2:34 PM, "burlen" <<a href="burlen.loring@gmail.com">burlen.loring@gmail.com</a>> wrote:<BR>
<BR>
</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>Ken,<BR>
Some bad news, this patch didn't solve the problem, the holes returned<BR>
on my first run.<BR>
Burlen<BR>
<BR>
<BR>
Moreland, Kenneth wrote:<BR>
> That was not intended to be a solution, but rather a diagnostic. My<BR>
> guess is that there are precision errors in the rasterization when the<BR>
> viewport is shifted. Could you restore vtkIceTRenderManager and try<BR>
> the attached patch to IceT?<BR>
><BR>
> -Ken<BR>
><BR>
><BR>
> On 12/10/09 12:26 PM, "burlen" <<a href="burlen.loring@gmail.com">burlen.loring@gmail.com</a>> wrote:<BR>
><BR>
> Hi Ken,<BR>
><BR>
> it seems to have solved the problems. I say that with fingers<BR>
> crossed, I<BR>
> haven't seen holes any since your suggested changes, where before<BR>
> I was<BR>
> seeing them quite often, popping up from time to time.<BR>
><BR>
> Burlen<BR>
><BR>
> Moreland, Kenneth wrote:<BR>
> > Hmm. It is possible that the “floating viewport” feature of IceT<BR>
> could<BR>
> > be causing troubles with precision. Could you try adding<BR>
> ><BR>
> > icetDisable(ICET_FLOATING_VIEWPORT);<BR>
> ><BR>
> ><BR>
> > somewhere in the vtkIceTRenderManager::UpdateIceTContext() method and<BR>
> > see if the problem goes away?<BR>
> ><BR>
> > -Ken<BR>
> ><BR>
> ><BR>
> > On 12/7/09 10:11 AM, "burlen" <<a href="burlen.loring@gmail.com">burlen.loring@gmail.com</a>> wrote:<BR>
> ><BR>
> > Hi Ken,<BR>
> > For that figure you mention I turned on "surface with edges" to<BR>
> > show the<BR>
> > cell size better. Sorry I can see how that could be confusing. But<BR>
> > just<BR>
> > to clarify, there aren't actually any holes in the surface.<BR>
> ><BR>
> > Here is another zoom in of the same area where "surface with<BR>
> edges" is<BR>
> > off and you can see that there are no holes.<BR>
> > <a href="http://nashi-submaster.ucsd.edu/movies/PV/bug-zoom.png">http://nashi-submaster.ucsd.edu/movies/PV/bug-zoom.png</a><BR>
> ><BR>
> > Now I also have hit a case where after running through D3 I got a<BR>
> hole<BR>
> > at the process boundary. this run had 80 processes, the surface shown<BR>
> > has dimensions of 5.5 x 10 units with 1500 x 2727quads with side<BR>
> > 0.0036<BR>
> > units.<BR>
> > <a href="http://nashi-submaster.ucsd.edu/movies/PV/bug-d3.png">http://nashi-submaster.ucsd.edu/movies/PV/bug-d3.png</a><BR>
> ><BR>
> > I am only seeing this with the small quads and in parallel at process<BR>
> > boundaries.<BR>
> ><BR>
> > Burlen<BR>
> ><BR>
> ><BR>
> > Moreland, Kenneth wrote:<BR>
> > > Burlen,<BR>
> > ><BR>
> > > For the zoom in, you say there are no holes/lines, but in the<BR>
> image I<BR>
> > > see a grid of lines. It looks like you have a bunch of little quads<BR>
> > > with spacing in between them. Is this the case? If so, then the<BR>
> > “hole”<BR>
> > > artifacts you see on the bottom of the screen are probably simply<BR>
> > > aliasing artifacts. They are places where the pixel happens to<BR>
> align<BR>
> > > right where the gap is.<BR>
> > ><BR>
> > > I can’t think of an easy way around this (other than to modify your<BR>
> > > data to remove the gaps, if that makes sense). Anti-aliasing<BR>
> > > techniques such as oversampling or smoothing would probably fix the<BR>
> > > problem, but they would also break the parallel rendering so<BR>
> they are<BR>
> > > no good.<BR>
> > ><BR>
> > > -Ken<BR>
> > ><BR>
> > ><BR>
> > > On 12/5/09 12:18 AM, "burlen" <<a href="burlen.loring@gmail.com">burlen.loring@gmail.com</a>> wrote:<BR>
> > ><BR>
> > > its ugly but I get a lot better performance by splitting the<BR>
> work up<BR>
> > > dynamically with a small grain size. in the run shown below<BR>
> there are<BR>
> > > only 16 processes but there are a whole lot of process boundaries.<BR>
> > ><BR>
> > > I was able to reproduce it on a second system today.<BR>
> > ><BR>
> > > these holes are pretty non-deterministic in where they show up.<BR>
> > moving<BR>
> > > the camera they can show up in different places. Which makes<BR>
> sense if<BR>
> > > this is related to some parallel rendering/finite precision issue<BR>
> > with<BR>
> > > all those process boundaries. The small size of the quads are<BR>
> also a<BR>
> > > factor, because I didn't ever notice it before when using larger<BR>
> > > quads.<BR>
> > ><BR>
> > > I saved the data as a legacy file and opening it on my desktop<BR>
> > > there are<BR>
> > > no issues, so its definitely a parallel only issue. Also running<BR>
> > > through<BR>
> > > D3 seems to fix it, but the issue may still be there because<BR>
> with the<BR>
> > > minimal number of process boundaries its much less likely to<BR>
> get the<BR>
> > > camera in just the right position.<BR>
> > ><BR>
> > > Berk Geveci wrote:<BR>
> > > > Ouch. That's very distributed :-) Does the problem go away<BR>
> when you<BR>
> > > > decrease the number of partitions?<BR>
> > > ><BR>
> > > > On Thu, Dec 3, 2009 at 10:55 AM, burlen <<a href="burlen.loring@gmail.com">burlen.loring@gmail.com</a>><BR>
> > > wrote:<BR>
> > > ><BR>
> > > >> I'm seeing lines where the background shows through a surface<BR>
> > > polydata of<BR>
> > > >> quads. When I zoom into the region to investigate the holes are<BR>
> > > gone. Moving<BR>
> > > >> the image around the holes appear in different places. They<BR>
> > > depend on camera<BR>
> > > >> position. In this surface there are 2.5E6 quads. the area is<BR>
> > > 10x16 units and<BR>
> > > >> the number of quads is 1250x2000. each quad has 0.008 units on a<BR>
> > > side. I<BR>
> > > >> hadn't seen the holes before going to this higher resolution.<BR>
> > > It's likely<BR>
> > > >> that the hole is near a process boundary, in my polydata filter<BR>
> > > each process<BR>
> > > >> adds his quads to his output polydata, in this run the quads are<BR>
> > > distributed<BR>
> > > >> in strips of 512 as needed.<BR>
> > > >><BR>
> > > >> 3 holes/lines in bottom half of the image (black background<BR>
> > > shows through):<BR>
> > > >> <a href="http://nashi-submaster.ucsd.edu/movies/PV/bug.png">http://nashi-submaster.ucsd.edu/movies/PV/bug.png</a><BR>
> > > >><BR>
> > > >> zoom in no holes/lines:<BR>
> > > >> <a href="http://nashi-submaster.ucsd.edu/movies/PV/bug-zoom-2.png">http://nashi-submaster.ucsd.edu/movies/PV/bug-zoom-2.png</a><BR>
> > > >><BR>
> > > >> process boundaries (from process id filter):<BR>
> > > >> <a href="http://nashi-submaster.ucsd.edu/movies/PV/bug-procs.png">http://nashi-submaster.ucsd.edu/movies/PV/bug-procs.png</a><BR>
> > > >><BR>
> > > >> Should PV be able to handle a polydata distributed like this?<BR>
> > > >><BR>
> > > >><BR>
> > > >><BR>
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> > ><BR>
> > ><BR>
> > > **** Kenneth Moreland<BR>
> > > *** Sandia National Laboratories<BR>
> > > ***********<BR>
> > > *** *** *** email: <a href="kmorel@sandia.gov">kmorel@sandia.gov</a><BR>
> > > ** *** ** phone: (505) 844-8919<BR>
> > > *** web: <a href="http://www.cs.unm.edu/~kmorel">http://www.cs.unm.edu/~kmorel</a><BR>
> <<a href="http://www.cs.unm.edu/%7Ekmorel">http://www.cs.unm.edu/%7Ekmorel</a>><BR>
> > <<a href="http://www.cs.unm.edu/%7Ekmorel">http://www.cs.unm.edu/%7Ekmorel</a>> <<a href="http://www.cs.unm.edu/%7Ekmorel">http://www.cs.unm.edu/%7Ekmorel</a>><BR>
> > ><BR>
> ><BR>
> ><BR>
> ><BR>
> ><BR>
> ><BR>
> > **** Kenneth Moreland<BR>
> > *** Sandia National Laboratories<BR>
> > ***********<BR>
> > *** *** *** email: <a href="kmorel@sandia.gov">kmorel@sandia.gov</a><BR>
> > ** *** ** phone: (505) 844-8919<BR>
> > *** web: <a href="http://www.cs.unm.edu/~kmorel">http://www.cs.unm.edu/~kmorel</a><BR>
> <<a href="http://www.cs.unm.edu/%7Ekmorel">http://www.cs.unm.edu/%7Ekmorel</a>> <<a href="http://www.cs.unm.edu/%7Ekmorel">http://www.cs.unm.edu/%7Ekmorel</a>><BR>
> ><BR>
><BR>
><BR>
><BR>
><BR>
><BR>
> **** Kenneth Moreland<BR>
> *** Sandia National Laboratories<BR>
> ***********<BR>
> *** *** *** email: <a href="kmorel@sandia.gov">kmorel@sandia.gov</a><BR>
> ** *** ** phone: (505) 844-8919<BR>
> *** web: <a href="http://www.cs.unm.edu/~kmorel">http://www.cs.unm.edu/~kmorel</a> <<a href="http://www.cs.unm.edu/%7Ekmorel">http://www.cs.unm.edu/%7Ekmorel</a>><BR>
><BR>
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<BR>
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**** Kenneth Moreland<BR>
*** Sandia National Laboratories<BR>
*********** <BR>
*** *** *** email: <a href="kmorel@sandia.gov">kmorel@sandia.gov</a><BR>
** *** ** phone: (505) 844-8919<BR>
*** web: <a href="http://www.cs.unm.edu/~kmorel">http://www.cs.unm.edu/~kmorel</a><BR>
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