[vtkusers] Animation of multiple input files in VTK

[Dominik Szczerba]

> When I load this sequence in Paraview, it is able to run very smoothly
> (after the first run, which takes some time) while still allowing the user
> to interact. Does anyone know how Paraview does this?

Probably by caching. Why not precompute marching cubes prior to rendering?

Dominik

>
> Tijmen
>
> On Wed, Jul 6, 2011 at 5:46 PM, Shashwath T.R. <trshash at gmail.com> wrote:
>>
>> Why not have multiple vtkMarchingCubes instances - one for each input, and
>> then multiple mapper/actor sets? You could select which one you want to work
>> on, and make the rest invisible...
>> Shash
>>
>> On Wed, Jul 6, 2011 at 4:37 PM, Tijmen Klein <T.R.Klein at student.rug.nl>
>> wrote:
>>>
>>> This is what I do. I set up the whole scene, load in all the different
>>> readers, and connect the first reader to the vtkMarchingCubes. Then I use a
>>> timer that calls an update function every second. This update function sets
>>> the inputconnection of the vtkMarchingCubes to the current reader
>>> (contours->setInputConnection(reader[current]->getOutputPort()). This is
>>> working, but results in small (but very noticable) hickups in the
>>> interaction. I think this is because the isosurfaces have to be
>>> re-calculated every time. That's why I think that I will need an array of
>>> vtkMarchingCubes too.
>>>
>>> Tijmen
>>>
>>> On Wed, Jul 6, 2011 at 11:02 AM, Dominik Szczerba <dominik at itis.ethz.ch>
>>> wrote:
>>>>
>>>> You should update your reader only from a callback function once you
>>>> have your scene/camera/etc set up...
>>>>
>>>> Dominik
>>>>
>>>> On Wed, Jul 6, 2011 at 10:51 AM, Tijmen Klein <T.R.Klein at student.rug.nl>
>>>> wrote:
>>>> > Thank you for the reply. First of all, I'm not trying to export a
>>>> > animation;
>>>> > it should be realtime and allowing the user to navigate the scene.
>>>> >
>>>> > I'm currently applying the fist technique (update the reader in a
>>>> > loop).
>>>> > Technically this works fine, but it is really slow and also blocks the
>>>> > mean
>>>> > thread of the program (the program simply freezes when switching
>>>> > between 2
>>>> > frames). A possible solution that I came up with is the following:
>>>> > create N
>>>> > pipelines (up to the mapper), where N is the number of frames. This
>>>> > mean I
>>>> > can load the data first, create the isosurfaces and then based on the
>>>> > current time let the actor point to the corresponding mapper. This
>>>> > would
>>>> > mean that all the calculations are already completed.
>>>> >
>>>> > Is this a viable solution? It feels a bit hack-ish to do it like this.
>>>> >
>>>> > Tijmen
>>>> >
>>>> > On Tue, Jul 5, 2011 at 4:00 PM, Dominik Szczerba
>>>> > <dominik at itis.ethz.ch>
>>>> > wrote:
>>>> >>
>>>> >> There are a few possibilities. The simplest would be to update the
>>>> >> reader in a loop and dumping screen renderings. More sophisticated
>>>> >> would be to import them first into a temporal dataset and then
>>>> >> request
>>>> >> a specific time value.
>>>> >>
>>>> >> Dominik
>>>> >>
>>>> >> On Tue, Jul 5, 2011 at 2:57 PM, Tijmen Klein
>>>> >> <T.R.Klein at student.rug.nl>
>>>> >> wrote:
>>>> >> > I'm trying to animate multiple input files. These files are in the
>>>> >> > legacy
>>>> >> > VTK format (.vtk), and named filename[x].vtk, where [x] is an
>>>> >> > integer. A
>>>> >> > contourfilter is used to generate isosurfaces, and these
>>>> >> > isosurfaces
>>>> >> > should
>>>> >> > be animated.
>>>> >> >
>>>> >> > This is behaviour that is quite easy to achieve in Paraview (open
>>>> >> > the
>>>> >> > files,
>>>> >> > apply contour filter, choose a frame or click play). How can
>>>> >> > something
>>>> >> > similar be achieved in VTK? It should be possible to create a
>>>> >> > time-dependent
>>>> >> > animation, but also manually set the current frame. I thought of
>>>> >> > creating
>>>> >> > multiple InputReaders, and have the 'current' reader's outputport
>>>> >> > connected
>>>> >> > to the input port of the contour filter. But I think this would not
>>>> >> > be
>>>> >> > very
>>>> >> > efficient, since it's not possible to cache the results in this
>>>> >> > way.
>>>> >> > This
>>>> >> > would mean that all the calculations happen again when the
>>>> >> > animations
>>>> >> > restarts from frame 1. What would be a better solution?
>>>> >> >
>>>> >> > Cheers,
>>>> >> > Tijmen
>>>> >> >
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>>>> >
>>>> >
>>>
>>>
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>
>
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