[Paraview] Animation with sudden large intervals between consecutive frames

Utkarsh Ayachit utkarsh.ayachit at kitware.com
Mon Jan 14 17:47:57 EST 2013


Interesting. I am not sure what it could be. Another option is to try
disabling the use of offscreen rendering for screenshots (by
unchecking "Use Offscreen Rendering for Screenshots" in the "Settings"
dialog on the "Render View" page (at the bottom of that page).

Utkarsh

On Mon, Jan 14, 2013 at 11:06 AM, Tom Fahner <tom.fahner at gmail.com> wrote:
> Hello Utkarsh,
>
> Well in fact I have used both. I had used a python script before, which gave
> a similar behavior, but in that case the unusual large intervals were about
> 15 minutes instead of 8 hours. I also noticed that there was something wrong
> in my setup using the python script, so when I redid the animation I simply
> used the GUI to check the setup more rigorously and decided not to use the
> python script.
>
> A bit more info on the python script:
>
> With the python script I also assumed it may have been related to the actual
> screen being rendered at the moment that the large intervals showed up. This
> because I used VNC to log into the machine for rendering and the screen was
> locked with ParaView running for most of the time. I just unlocked the
> screen occasionally to have a look at the progress from time to time and I
> could imagine this may have influenced the rendering. Later I also saw a 15
> min. interval between two pngs which were created in the middle of the
> night, meaning the screen was probably still locked, so I assumed that me
> unlocking the screen could not have been the reason. Fifteen minutes between
> two frames can be accepted if this happens once in 100 frames or so, but 8
> hours is just too much.
>
> At the moment I started the animation from the GUI again, but with the
> "Cache Geometry" unchecked as you suggested. I will check the results of
> that setting tonight.
>
> Regards,
> Tom
>
>
> 2013/1/14 Utkarsh Ayachit <utkarsh.ayachit at kitware.com>
>>
>> Tom,
>>
>> I wonder if caching is causing these issues. Are you using the
>> ParaView GUI or a Python script? If  the GUI, can you disable caching
>> (uncheck "Cache Geometry" from the "Animation" page in the "Settings"
>> dialog.
>>
>> Utkarsh
>>
>> On Mon, Jan 14, 2013 at 5:50 AM, Tom Fahner <tom.fahner at gmail.com> wrote:
>> > Dear all,
>> >
>> > For some reason I noticed that ParaView has some large intervals between
>> > writing a PNG for consecutive frames of an animation. Normally there is
>> > about one minute between the timestamp of two PNGs, but sometimes there
>> > is
>> > suddendly a gap of 8 hours:
>> >
>> >  141K Jan 13 15:56 New_Volume_.0118.png
>> >  141K Jan 13 15:58 New_Volume_.0119.png
>> >  139K Jan 13 15:59 New_Volume_.0120.png
>> >  139K Jan 13 16:00 New_Volume_.0121.png
>> >  138K Jan 14 00:34 New_Volume_.0122.png
>> >  139K Jan 14 00:35 New_Volume_.0123.png
>> >  139K Jan 14 00:36 New_Volume_.0124.png
>> >
>> > There are multiple occasions where these large intervals happen but this
>> > does not happen at a regular interval of the animation. There does seem
>> > to
>> > be a relation with the amount of memory that is used, since there is a
>> > sudden decrease in memory used right after "Jan 14 00:34". Below I will
>> > describe my animation and setup. I hope anyone can give an explanation
>> > for
>> > the behavior.
>> >
>> > During the weekend I have created an animation of a mixing tank using
>> > volume
>> > rendering of the concentration of some chemicals in the tank. It is a
>> > reasonably large CFD simulation performed with OpenFOAM. There are about
>> > 15
>> > million cells (tetrahedrals and prismatic layer), but not extremely
>> > large. I
>> > saved the concentration every 0.25 seconds for a 120s simulation. We
>> > have
>> > ParaView 3.98.0 installed on this machine and it was the only program
>> > running at the time. I have made the animation with ffmpeg after
>> > ParaView
>> > made the frames as consecutive pngs. Besides the volume rendering of the
>> > concentration, the walls of the tank where shown with a fixed opacity of
>> > 0.3
>> > and the internal structure (some rotors and baffles) where present as
>> > well.
>> > Although the simulation use the MRF concept, I did mimick the rotation
>> > of
>> > the rotors using the transform filter. Using the "cool to warm" preset
>> > for
>> > visualization I could nicely set the opacity to 0 when the concentration
>> > was
>> > in the allowed range and it showed red in case of too high
>> > concentration, of
>> > blue when too low. The resulting animation is satisfactory, I just
>> > wonder
>> > what can be done to make sure these large intervals between writing
>> > images
>> > do not happen.
>> >
>> > Hope someone can help, if you need more information, please let me know.
>> >
>> > Regards,
>> > Tom
>> >
>> > --
>> > T.C. Fahner
>> > e: tom.fahner at gmail.com
>> >
>> >
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>
>
>
>
> --
> T.C. Fahner
> e: tom.fahner at gmail.com
> t: +31-6-52642814
> a: van Lodensteynstraat 24
>     2612 SE Delft
>     Netherlands


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