[vtkusers] vtkVisibleCellSelector and vtk 6.2

[David E DeMarle]

On Tuesday, May 20, 2014, Ahmet Doğan <isimtic at gmail.com> wrote:

>  frustum behaves like box clip doesn't it?
>

There are differences, but yes very similar.


>  I just need to extract cells by user view or like xy xz yz axis. like
> taking picture I don't need behind of dataset how can it be done? not
> possible with vtk?
>

I'ld love to be proven wrong but I don't think so, not in all cases. It
boils down to occlusion culling.

Zooming lessens the pixel resolution problem in scan conversion or ray
casting, but isn't perfect.

Extract surface into normal generation into frustum dotted with view
vector and cull the non negative results is close but it will get some
corner cases wrong too. It isn't resolution dependent at least.

I'ld like to hear about any other solutions out there since the
question comes up every once in a while.


> On 21.05.2014 03:54, David E DeMarle wrote:
>
Not much. It is a limitation of the screen space algorithm whch can pick at
> most one cell per pixel.
>
>  Frustum selection is an object space algorithm and doesn't have the same
> limitation, but it can not cull occluded cells.
>
> On Tuesday, May 20, 2014, Ahmet Doğan <isimtic at gmail.com<javascript:_e(%7B%7D,'cvml','isimtic at gmail.com');>>
> wrote:
>
>>
>> On 21.05.2014 03:21, Ahmet Doğan wrote:
>>
>>> On 21.05.2014 03:12, Ahmet Doğan wrote:
>>>
>>>> with vtkHardwareSelector cells are changing on zooming How can I
>>>> disable it.
>>>>
>>>> Please check the image I added
>>>>
>>>> thank you
>>>>
>>>>
>>>> On 20.05.2014 21:18, Bill Lorensen wrote:
>>>>
>>>>> It has been replaced by vtkHardwareSelector
>>>>>
>>>>>
>>>>> On Tue, May 20, 2014 at 2:01 PM, Ahmet Doğan <isimtic at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> hi,
>>>>>>
>>>>>> What's happened vtkVisibleCellSelector in vtk 6 and up. I cant see any
>>>>>> information on migrate page
>>>>>>
>>>>>> Kind regards.
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>>
>
> --
> David E DeMarle
> Kitware, Inc.
> R&D Engineer
> 21 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-881-4909
>
>
>

-- 
David E DeMarle
Kitware, Inc.
R&D Engineer
21 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-881-4909
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