[vtkusers] update scalars of vtkPoints

[Hagen Mölle]

Hi again,

After all I realized that everything is fine with my code. The problem 
is the vtkDelaunay filter I use. I need it for retrieving cutplanes and 
isoplanes from the dataset. So I am sorry for not mentioning this 
before. In 2d mode this filter works fast. In 3D mode with lots of 
points the filter needs a lot more time for calculation.

So finally I have to think about the presentation of the measured data. 
Maybe the best way is to reduce the number of points by triliniar 
interpolation.

Thanks again for your help,

Hagen

> Hi Hagen,
>
> Did you compiled VTK in Debug mode, or Release ?
> Are you sure that the time you are giving do not include the time to
> update the dataset ?
> In which language is your code ? (C++, Java, Python, TCL...)
>
> Seb
>
> 2010/7/1 Hagen Mölle<h.moelle at googlemail.com>:
>    
>> Hi again,
>>
>> using scalars->Modified() works. But now I returned to start. The
>> visualization update of the vtkUnstructuredGrid with for example 7000 points
>> takes about 40 seconds. So there is no difference in time consumption
>> between creating a new dataset or updating the old dataset.
>>
>> I do not really understand why it takes vtk over 40 seconds to update the
>> scalars in visualization of only 7000 points (vtkUnstructuredGrid). Is there
>> any else I can do to bring down the update time?
>>
>> Hagen
>>      
>>> Hi Hagen,
>>>
>>> did you also try scalars->Modified() instead?
>>>
>>> With Modified() you tell the pipeline that the data object has to be
>>> updated (also everything coming after this object in pipeline). You might
>>> forgot to run Update() on your mapper the vtkUnstructedGrid is attached to
>>> (or any other object that has Update() and is connected after the grid in
>>> pipeline row). You might also forgot to call the Render() method to update
>>> the renderer?
>>>
>>> Hope this helps!
>>>
>>> Sebastian Barth
>>>
>>> -----Ursprüngliche Nachricht-----
>>> Von: Hagen Mölle [mailto:h.moelle at googlemail.com]
>>> Gesendet: Donnerstag, 1. Juli 2010 14:16
>>> An: Barth, Sebastian
>>> Cc: John Drescher; vtkusers at vtk.org; sebastien.jourdain at kitware.com
>>> Betreff: Re: AW: [vtkusers] update scalars of vtkPoints
>>>
>>> Hi Sebastian,
>>>
>>> Thanks for your help. I got it working with vtkPolyData in my 2D
>>> visualization.
>>>
>>> In my 3D visualization of measured points I still have the problem that
>>> the scalars do not change. There I use vtkUnstructuredGrid instead of
>>> vtkPolyData. Right now the update routine of the scalars looks like this
>>> (pseudo code):
>>>
>>> scalars = vtkDataSet->GetPointData()->GetScalars()
>>> for(number of scalars)
>>> {
>>>       update each scalar
>>> }
>>> vtkDataSet->Modified()
>>>
>>> The code is compiling for vtkUnstructuredGrid and vtkPolyData. But it
>>> seems I have to do something additional to update the scalars of the
>>> vtkUnstructuredGrid.
>>>
>>> Any idea?
>>>
>>> Hagen
>>>
>>>
>>>
>>>        
>>>> Hello Hagen,
>>>>
>>>> did you forget to call Modified() of the vtkPolyData after altering the
>>>> points? Otherwise the vtkPolyData does not know that their points, scalars
>>>> or cells were changed.
>>>>
>>>> Sebastian Barth
>>>>
>>>> -----Ursprüngliche Nachricht-----
>>>> Von: vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] Im
>>>> Auftrag von Hagen Mölle
>>>> Gesendet: Donnerstag, 1. Juli 2010 08:26
>>>> An: John Drescher; vtkusers at vtk.org; sebastien.jourdain at kitware.com
>>>> Betreff: Re: [vtkusers] update scalars of vtkPoints
>>>>
>>>> On 06/30/2010 06:14 PM, John Drescher wrote:
>>>>
>>>>
>>>>          
>>>>> 2010/6/30 Sebastien Jourdain<sebastien.jourdain at kitware.com>:
>>>>>
>>>>>
>>>>>
>>>>>            
>>>>>> Hi Hagen,
>>>>>>
>>>>>> As you said, you can start by simply change the data on the fly and
>>>>>> call Render() once the change has been done. By change I mean point
>>>>>> location, scalar data and even point number.
>>>>>> But be aware that only one thread should be used in VTK otherwise they
>>>>>> have to be synchronized.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>              
>>>>> I think vtkPolyData->GetPointData->GetScalars()
>>>>>
>>>>> is where to start
>>>>>
>>>>> John
>>>>>
>>>>>
>>>>>
>>>>>            
>>>> Hi Sebastien and John,
>>>>
>>>> Thanks for pointing out how to change the scalars of the points on the
>>>> fly. So I need to alter the vtkDataArray which I get by
>>>> vtkPolyData->GetPointData->GetScalars(). Hopefully this will work.
>>>>
>>>> Yesterday I tried to set new scalars by using the following method:
>>>> vtkPolyData->GetPointData->SetScalars(vtkDoubleArray). So I did not
>>>> generate a new dataset. But the visualization did not change during
>>>> update. It seemed the old scalars where used during update.
>>>>
>>>> Hagen
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>>>>
>>>>          
>>>
>>>        
>>
>>