[Paraview] Bug or feature?

[Andy Bauer]

Hi,

Please keep the discussions on the mailing list so that everyone that wants
to can follow along.

I'm able to volume render by components as well as magnitude. It may be
that you need to play around with the Color Map Editor to get things as
you'd like them to look.

I'm not an expert on volume rendering but it seems to me like something is
wrong with your cell connectivity when I use the Extract Surface filter.
It's possible that this is also causing issues with the volume rendering
but I couldn't say for sure.

Andy

On Sun, May 7, 2017 at 5:20 AM, Cornelis Bockemühl <
cornelis.bockemuehl at gmail.com> wrote:

> This is my example, mostly stripped down to the core of the problem: see
> the Col2comp data array that has 2 components (see attached zipped vtu
> file). The model has something more than 600 cells, and in both components
> (comp1 and comp2) many of them are 0. In comp2 it is even all except 18 -
> and this can easily be seen in a "surface" view: almost everything is blue
> == 0. It can also be analyzed with cut and slice filters, so it is also the
> case "inside" the model.
>
> Now with a volume view this is completely different: comp2 looks as if
> indeed many cells have values "above blue"!
>
> But I must admit that initially I did not look well enough: also the
> volume view changes a little if I change between "magnitude", "comp1" and
> "comp2" - only that it does not look like matching the surface views at
> all: all cells except one actually have a 0 in one of the two components -
> which should be clearly visible also in the volume view I suppose!
>
> I could reproduce this behaviour not only on my self-compiled version 5.3
> paraview, but also in a downloaded and installed binary version 5.1.2
> (64-bit).
>
> In other words: I am a bit confused now! ;-)
>
> Regards,
> Cornelis
>
>
>
> 2017-05-07 0:49 GMT+02:00 Andy Bauer <andy.bauer at kitware.com>:
>
>> Hi,
>>
>> I am able to do a volume visualization for each component of a 3
>> component array (i.e. a vector) of both point and cell data in PV 5.3. This
>> was done with a both a vtkImageData and a vtkUnstructuredGrid. Once I
>> choose my 3 component array for volume rendering in the upper left corner
>> of the GUI, the default is the Magnitude but I can switch to each component
>> as well with the drop down dialog that is just to the right of where I
>> choose which array I want to pseudo-color by.
>>
>> Any chance you could share your dataset and specific instructions on how
>> you're doing things? Alternatively, you can use the Calculator filter to
>> extract one component of your multi-component array but this is a bit
>> computationally wasteful.
>>
>> Cheers,
>> Andy
>>
>> On Sat, May 6, 2017 at 12:15 PM, Cornelis Bockemühl <
>> cornelis.bockemuehl at gmail.com> wrote:
>>
>>> Dear Paraview users and experts,
>>>
>>> In some project I am generating a dataset that has a multi-component
>>> column as a result, with a variable number of columns depending on the
>>> problem. These data are "cell data" of some "unstructured grid", and I can
>>> nicely visualize it in Paraview, component by component.
>>>
>>> Only with the visualization as a "volume" I have problems: It seems that
>>> with this you can only visualize the "magnitude", while switching between
>>> the components does not work! This works only in other viewing modes, but
>>> the "volume" is sometimes very useful because you can look "inside" the
>>> volume.
>>>
>>> Now I am asking myself if this is a bug (with a certain chance to have
>>> it fixed or even fix it myself...) or a feature?
>>>
>>> I mean: the fact that "magnitude" is the default for displaying
>>> multi-component arrays already gives some hint in the direction: this type
>>> of columns is mostly intended to be used as coordinates! Which is actually
>>> not my case.
>>>
>>> Technically I could of course switch to just generating a set of
>>> single-component arrays instead of one multi-component array. I only did it
>>> otherwise because the columns are very closely related, so it looked like a
>>> good idea initially...
>>>
>>> Any hint or experience?
>>>
>>> Regards,
>>> Cornelis
>>>
>>> PS: I am using Paraview 5.3 on Windows 64bit
>>>
>>> --
>>> Cornelis Bockemühl
>>> Basel, Schweiz
>>>
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>>
>
>
> --
> Cornelis Bockemühl
> Basel, Schweiz
>
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