[Paraview] Maybe a silly question?

[wastrel at gmail.com]

Thanks again, and I took a look on the programmable filter code. In my case
the block consists of more than 1 million tetrahedrons and it will be time
consuming to run iterations. Is there a way that I can export the cells and
their corresponding point information to a numpy array? The ultimate goal is
to calculate the volume of each tetrahedron.

Your help is much appreciated!

Ken



On Wed, Mar 23, 2011 at 4:45 PM, David Thompson <dcthomp at sandia.gov> wrote:

>
>  I have an Exodus II type file loaded into Paraview and trying to get the
>>>> point ID for a group of cells. I know for vtk type object there are
>>>> functions like GetCell(), GetPoint()
>>>>
>>>>  I assume you're talking about using Python from ParaView?
>>>
>>
>> Yup, that's exactly what I am doing here.
>>
>
> There are 2 ways to use Python in ParaView: writing a programmable filter
> and scripting the user interface. The former is evaluated on the server
> where you can get access to (at least a portion of) the actual dataset. The
> latter is evaluated on the client, which does not have access to the
> datasets -- instead it has proxy objects that send messages to the servers,
> telling them what to do. So, you can access the points and cells from within
> a programmable filter, but not from within a client-side script.
>
>
>
>>  and just wonder if there are such kind of routines available for Exodus
>>>> II files.
>>>>
>>>>  Yes, the ExodusII reader outputs VTK objects in a multiblock dataset.
>>> You can use GetCell(), GetPoint(), and such on each individual block... you
>>> just have to decide on a particular block. The ExodusII reader separates
>>> things into blocks because each one may have different point and/or cell
>>> variables. There are actually 2 levels of blocks; the top level segregates
>>> datasets into groups that correspond to exodus blocks vs. sets. The second
>>> level breaks individual blocks or sets into separate datasets. Does that
>>> help?
>>>
>>>
>> I am new in dealing with ex2 file, could you please be detailed? There is
>> just one block in the dataset, so how to get the vtk object out from it so I
>> can access the points and cells?
>>
>
>
> See the section of this page
>  http://www.vtk.org/Wiki/Python_Programmable_Filter
> named "Dealing with Composite Datasets". It describes how to iterate over
> all of the blocks in the dataset and run a function (in this case, one named
> "flatten") on each block.
>
>        David
>
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