[vtkusers] problems with transient unstructured volume rendering

[David E DeMarle]

That particular filter has only four parameters, produce data at
discrete locations or analytically across the temporal domain, grow
(vary number of cells or not), and x and y amplitude for it to move
across over time.

It produces at most 5 cells I think, so you will have to write some
code if the bug is only exposed by higher resolution data. The point
was to make something small and predictable to test vtk's support for
time varying data.

More details about time in VTK can be found here
http://www.vtk.org/Wiki/VTK/Time_Support

David E DeMarle
Kitware, Inc.
R&D Engineer
28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x109



On Tue, Dec 15, 2009 at 3:33 PM, Dominik Szczerba <dominik at itis.ethz.ch> wrote:
> I will be happy to.
>
> While I download and compile CVS, would you kindly post an example how to
> generate such a transient dataset (at a desired resolution for inaccurate
> but fast rendering)?
>
> Dominik
>
> David E DeMarle wrote:
>>
>> In CVS, time source produces an unstrucured grid that changes over
>> time. Can you reproduce the problem with that?
>>
>> David E DeMarle
>> Kitware, Inc.
>> R&D Engineer
>> 28 Corporate Drive
>> Clifton Park, NY 12065-8662
>> Phone: 518-371-3971 x109
>>
>>
>>
>> On Tue, Dec 15, 2009 at 3:25 PM, Dominik Szczerba <dominik at itis.ethz.ch>
>> wrote:
>>>
>>> I am quite happy with static unstructured volume rendering.
>>>
>>> The problems arise when I request subsequent timesteps:
>>>
>>>       while time<=timeEnd:
>>>               executive = reader.GetExecutive()
>>>               executive.SetUpdateTimeStep(0,time)
>>>               reader.Modified()
>>>               window.Render()
>>>
>>>
>>> This results in changing but wrong colors in my volume. Don't know
>>> exactly
>>> what is rendered, but it is certainly different from rendering the
>>> subsequent timestep from scratch. The situation is remedied with the
>>> following code:
>>>
>>>       while time<=timeEnd:
>>>               executive = reader.GetExecutive()
>>>               executive.SetUpdateTimeStep(0,time)
>>>               reader.Modified()
>>>               renderer.RemoveVolume(volume)
>>>               volume = vtkVolume()
>>>               volume.SetMapper(volumeMapper)
>>>               volume.SetProperty(volumeProperty)
>>>               renderer.AddVolume(volume)
>>>               window.Render()
>>>
>>> Looks like something is not reset, but my color/transfer functions are
>>> static (not changing with the changing scalar ranges).
>>>
>>> I could just shrug and go on, but this does not look fine to me so I
>>> thought
>>> I'd better ask if it is not a problem somewhere in VTK that should be
>>> reported.
>>>
>>> Dominik
>>>
>>> PS. Following the great example of David D. I wanted to set up a wiki
>>> example, but unfortunately I was unable to find a small (transient
>>> unstructured) example dataset or an example code to generate one.
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>>
>
>