[vtkusers] Voxel Data from MATLAB to VTK

[David Gobbi]

My familiarity with Titan is nil, but "git blame" tells me that the
vtkMatlabMexAdapter.h has been in VTK since 2009-12-14.  It should be
built whenever VTK_USE_MATLAB_MEX is turned ON in CMake.

I haven't ever used the new VTK matlab engine stuff, so hopefully
someone that is familiar with it will chime in.

   David


On Mon, May 17, 2010 at 12:29 PM, Brian Davis <bitminer at gmail.com> wrote:
> The latest I found suports using flat arrays as you suggest and as I tried
> to do and reshaping with and example I found at:
>
> http://www.kitware.com/InfovisWiki/index.php/Matlab_Interface
>
> The vtkMatlabMexAdapter looks exactly like what I am looking for
>
> --snip
>
>  edata =
> vtkMatlabMexAdapter::mxArrayTovtkDataArray(const_cast<mxArray*>(prhs[0]));
>
>    id->SetDimensions(300,300,1);
>    id->SetOrigin(0.0,0.0,0.0);
>    id->SetSpacing(1.0,1.0,1.0);
>    id->SetScalarTypeToUnsignedChar();
>    id->SetNumberOfScalarComponents(3);
>    id->SetWholeExtent(0,299,0,299,0,0);
>
>    id->GetPointData()->SetScalars(edata);
>
> --end snip--
>
> However a search in my tree vtkMatlabMexAdapter returns nothing.  Seems to
> be a part of Titan?
>
> Though it looks as thought it is in latest:
>
> http://www.vtk.org/doc/nightly/html/classvtkMatlabMexAdapter.html
>
>
> Brian
>
>
> On Mon, May 17, 2010 at 11:25 AM, David Gobbi <david.gobbi at gmail.com> wrote:
>>
>> Hi Brian,
>>
>> It's much easier to use flat arrays to store n-dimensional data in
>> VTK.  This is how VTK manages structured data such as vtkImageData.
>> Then all you need to do when moving the data into Matlab is reshape
>> the flat array into an n-dimensional array by using the known
>> dimensions of the desired n-dimensional array.
>>
>> For example, when moving vtkImageData to Python's NumPy, I grab the
>> Dimensions and NumberOfScalarComponents from the image data and use
>> that information to reshape the array into a 3D or 4D array.  The same
>> could be done with Matlab, I think.
>>
>>   David
>>
>>
>> On Mon, May 17, 2010 at 10:15 AM, Brian Davis <bitminer at gmail.com> wrote:
>> > So latest in my search for how to do this I came across:
>> >
>> > http://www.vtk.org/doc/nightly/html/classvtkArrayData.html
>> >
>> > With the important part:
>> >
>> > --snip--
>> > Because vtkArray cannot be stored as attributes of data objects (yet), a
>> > "carrier" object is needed to pass vtkArray through the pipeline.
>> > vtkArrayData  acts as a container of zero-to-many vtkArray instances,
>> > which
>> > can be retrieved via a zero-based index. Note that a collection of
>> > arrays
>> > stored in vtkArrayData  may-or-may-not have related types, dimensions,
>> > or
>> > extents.
>> > --end snip--
>> >
>> > and looking at the api and input types for ImageData and the
>> > volumeMappers
>> > the input to these appears to only be a route that involves vtkDataSet.
>> > I
>> > get the feeling that using the Array classes in an attempt to create
>> > image
>> > data is an futile attempt at "round hole square plug" am I correct with
>> > this
>> > assessment?  Array data appears to have a path to filters and not image
>> > data.  Is this correct?
>> >
>> > Which means I may have to result to awful for loops as in the examples.
>> > I
>> > also looked at the examples for
>> >
>> > Brian
>> >
>> > _______________________________________________
>> > 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
>> >
>> >
>
>
>
> --
> Brian J. Davis
>
>