[Paraview] tube filter, surfaces aren't closed?

[Moreland, Kenneth]

I'm guessing that this is a z-buffer precision issue.  The nVidia card must be using a higher precision z-buffer or doing something else that is preventing the z-fighting that appears to be happening in the Mesa implementation.

-Ken


On 1/18/10 11:47 AM, "burlen" <burlen.loring at gmail.com> wrote:

Yes, that is the case. There are 200 lines , each a single cell , and
the pvtp reader splits them up fairly evenly amongst processes to begin
with. D3 is moving stuff around but it doesn't noticeably change the result.

Moreland, Kenneth wrote:
> Looking at the mesa-artifacts-decomp.png image, it appears that you
> have many tubes that are coincident (or at least close to coincident).
>  There might be z-buffer resolution problems.  What happens if you run
> the geometry through D3?
>
> -Ken
>
>
> On 1/15/10 10:28 AM, "burlen" <burlen.loring at gmail.com> wrote:
>
>     FYI, I re-organized the images illustrating the bug, and made a
>     comparison of nvidia to mesa rendering on two cases 1) the
>     artifacts 2)
>     the parallel inconsistency, and removed the older images.
>
>     1)
>     http://nashi-submaster.ucsd.edu/movies/PV/tube-filter-artifact/mesa-artifacts.png
>     http://nashi-submaster.ucsd.edu/movies/PV/tube-filter-artifact/nvidia-no-artifacts-decomp.png
>
>     2)
>     http://nashi-submaster.ucsd.edu/movies/PV/tube-filter-artifact/mesa-artifacts-decomp.png
>     http://nashi-submaster.ucsd.edu/movies/PV/tube-filter-artifact/nvidia-no-artifacts.png
>
>     burlen wrote:
>     > So you are right these are artifacts not holes. Nasty looking ones at
>     > that. zooming in enough makes the artifacts receded toward the egdes
>     > of the tube. After some experimentation I'm finding that this has
>     > something to do with mesa. It is reproducible only when using mesa.
>     > Hardware rendering works fine, no artifacts.
>     >
>     > There also looks to be two things going on, 1) the artifacts, 2)
>     > inconsistent selection of the visible faces on parallel runs.
>      This is
>     > shown here:
>     > http://nashi-submaster.ucsd.edu/movies/PV/tube-filter-artifact/decomp-8-procs.png
>     >
>     >
>     > I was using PV on this cluster fine back in dec to make very similar
>     > figures with stream tubes and didn't see any of these issues...
>     >
>     > I added the dataset to reproduce to the bug report.
>     >
>     > Moreland, Kenneth wrote:
>     >> It could be a rendering artifact.  What happens when you zoom into
>     >> the problem area?
>     >>
>     >> -Ken
>     >>
>     >>
>     >> On 1/14/10 12:24 AM, "burlen" <burlen.loring at gmail.com> wrote:
>     >>
>     >>     Any ideas as to why tubes from the tube filter aren't closed
>     >> surfaces
>     >>     now? screenshot:
>     >>     http://public.kitware.com/Bug/view.php?id=10139
>     >>
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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>
>     >>
>     >
>
>
>
>
>
>    ****      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>
>





   ****      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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