HI Gael, Saving each time step to a VTI file is very reasonable in the way that you are doing it. I would recommend doing that.
To assign times to each VTI file, I recommend also writing a .pvd file, which is an XML file that describes a list of files that can be loaded by ParaView. You can describe your VTI files in the .pvd file and assign a time to each VTI file. Please see http://www.paraview.org/Wiki/ParaView/Data_formats#PVD_File_Format for more details on the PVD file. Hope that helps, Cory On Thu, Nov 12, 2015 at 1:24 PM, lorieul <gael.lori...@uclouvain.be> wrote: > Hello, > > I wanted to know the cleanest way to save a custom array class instance > to a *.vti file with time information. I searched through the > documentation and found some threads in the mailing list archives but > could not find compelling answers (quite to my surprise… I'm sure the > information must be there somewhere…). > > I am designing a C++ software that performs CFD (Computational Fluid > Dynamics) simulations. I start from known initial conditions and iterate > in time. After each iteration, I know the definition of each of the flow > variables (e.g. I know the velocity field at each time step). I want to > save this information into a *.vti file so that I can visualise it with > paraview and (for instance) animate it. > > My code uses its own array class which I'll call DblArr. Hence when I > want to save a field to a file, I need to use a vtkImageData object and > copy all the data from the DblArr object into it. This means that for > each DblArr array I want to save, I need a corresponding vtkImageData > object (hence additional memory and computation costs). Is that the best > way to do so ? > > Besides, how do I store the time information ? Should I call : > > myImgData->GetInformation()->Set( > vtkDataObject::DATA_TIME_STEPS(), & currentTime, 1); > > Or is there a better way to do so ? (I found very little reference to > DATA_TIME_STEPS() in the documentation) > > Gael Lorieul > PhD student at Université catholique de Louvain > > > > > > Getting more into details : > > for each DblArr that I might want to save, I instanciate a Svr_vti > object (which is another custom class). The purpose of this class is to > perform the save operation to a *.vti file. It does three things : > 1. allocating memory i.e. instanciation of vtkImageData object at the > beginning of the simulation > 2. handling the copying of data from the DblArr object to the > vtkImageData > object > 3. writing the *.vti file. > > Once again, I have strong doubts that this is the best solution to my > problem… > > Currently I have a class called Svr_vti which holds : (amongst other > things) > @ a constructor > @ a save() member function > @ a vtkImageData member object called _ImgData > @ a vtkXMLImageDataWriter object called _Wrtr > @ a reference to a DblArr called _Arr > > Constructor(DblArr & MyArr) performs : > > _ImgData = vtkSmartPointer<vtkImageData>::New() > _Wrtr = vtkSmartPointer<vtkXMLImageDataWriter>::New() > _Arr = MyArr > // > _ImgData->SetDimensions(***,***,***); > _ImgData->AllocateScalars( VTK_DOUBLE, * ); > _ImgData->SetOrigin(***, ***, ***); > _ImgData->SetSpacing(***, ***, ***) > // > _Wrtr->SetInputData( _ImgData ); > > > save(DblArr &) member function performs : > > for each node (i,j,k) in domain : > double * pxl = _ImgData->GetScalarPointer(i,j,k) > for each component in vector<DblArr *> : > pxl[ind] = Arr(i,j,k, ind) > } > } > // > //The file name embeds the number of current time step > //Hence the file name is different each time save() is called > _Wrtr->SetFileName( *** ); > _Wrtr->Write(); > > Note : this is pseudo-code, it might contain syntax errors and/or > abreviations > > > > _______________________________________________ > 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 > > Search the list archives at: http://markmail.org/search/?q=vtkusers > > Follow this link to subscribe/unsubscribe: > http://public.kitware.com/mailman/listinfo/vtkusers > > -- Cory Quammen R&D Engineer Kitware, Inc.
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