[vtkusers] Fail to render big data of unstructured Grid

[Alex Malyushytskyy]

// windows XP platform with 3GB of RAM

32 bit Windows address space is limited to 4 GB per process and only
half of it is available for data by default.
Mostly likely you run out of it. You may try to start task manager and
see how memory grows.

So you  want to minimize memory usage.

You may try deleting unstructured grid (block) as soon it is added.
This will complicate iteration a bit unless you use backward iteration order.
This may or may not be sufficient.

In this case I would recommend to write all your unstructured grids on
the hard-drive,
and remove them from memory,

then load one, append to polydata, delete

and hope that total amount of data + single undsructured grid +
temporary instance of  vtkDataSetSurfaceFilter
fits the memory.


Regards,
    Alex

On Tue, Nov 22, 2011 at 7:18 AM, R M <mlokida at yahoo.fr> wrote:
> Hello,
> Here's my problem. I use vtk 5.8.0 on a windows XP platform with 3GB of RAM
> (it is an application using vtk and Qt). I have a geometry which is composed
> of about 2 000 000 hexadrons cells.  My geometry is composed of about 20
> blocks.
> Now, I want to transform my 20 unstructuredGrid blocks (in a
> vtkMultiBlockDataSet) in one polydata or unstructuredGrid.
> First, I have try the vtkMergeCells in order to have 1 vtkUnstructuredGrid.
> I have the following error:
> vtkDataArrayTemplate.cxx l 359 Unable to allocate 35,793,215 Elements of...
> (I don't have the end of the message).  The number (35,793,...) is not
> always the same.
> Now, I have decided to use the vtkAppendFilter. For that I use the following
> code :
> vtkAppendPolyData* append = vtkAppendPolyData::New();
>
> for(unsigned int i = 0; i < mbds->GetNumberOfBlocks(); ++i)
>     {
>         vtkDataSetSurfaceFilter* dssf = vtkDataSetSurfaceFilter::New();
>         dssf->PassThroughCellIdsOn();
>         dssf->PassThroughPointIdsOn();
>
>         dssf->SetInput( ptr_mbds->GetBlock(i) );
>         dssf->Update();
>
>         append->AddInput( dssf->GetOutput());
>
>         dssf->Delete();
>   }
>    append->Update();
> With this code, I have the same error. It occurs at line269 of
> vtkAppendPolyData.cxx ->  newStrips->Allocate(numCells*4); with numCells =
> 2251994
> I don't know why there is this multiplication *4 since we have the exact
> number of cells. May be the process will create more cells than it exists.
> Moreover, both method are very time consuming.
>
> So, can someone tell me what 's wrong with my methods and what can I do  to
> display my geometry ?
>
> Thank you.
>
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtkusers
>
>