[vtkusers] TIN to regular mesh

Bill Lorensen bill.lorensen at gmail.com
Sat Apr 13 14:34:39 EDT 2013 

// vtkCellDataToPointData is a filter that transforms cell data (i.e., data
// specified per cell) into point data (i.e., data specified at cell
// points). The method of transformation is based on averaging the data
// values of all cells using a particular point. Optionally, the input cell
// data can be passed through to the output as well



On Fri, Apr 12, 2013 at 8:33 AM, Bill Lorensen <bill.lorensen at gmail.com>wrote:

> Marc,
>
> I'm pretty sure is works with PointData and not CellData.
>
> Bill
>
>
> On Fri, Apr 12, 2013 at 7:08 AM, Marc Huber <marchuber.hft at gmx.de> wrote:
>
>>  This is exactly what I want thanks!
>>
>> It just doesnt take my scalar values to build regions
>>
>> i have scalar values like e.g.
>>   3548  3548  3549  3549  3549  3549  3549  3549  3550  3550
>> for each value I want to create regions if there is a connection
>> my problem is, that I just get 1 big region, but depending on my values i
>> should get about 100 regions
>>
>> My Code:
>>
>> polydata->GetCellData()->SetScalars(arr);   //arr contains my scalars for
>> each cell (Type: vtkFloatArray)
>> vtkSmartPointer<vtkPolyDataConnectivityFilter> regionFilter =
>> vtkSmartPointer<vtkPolyDataConnectivityFilter>::New();
>> regionFilter->SetInputConnection(polydata->GetProducerPort());
>>         regionFilter->ScalarConnectivityOn();
>>         regionFilter->SetFullScalarConnectivity(1);
>>         regionFilter->SetScalarRange(1,9090);
>>         regionFilter->SetExtractionModeToAllRegions();
>>         regionFilter->SetColorRegions(1);
>>         regionFilter->Update();
>> vtkSmartPointer<vtkPolyDataMapper> conMapper =
>> vtkSmartPointer<vtkPolyDataMapper>::New();
>>         conMapper->SetInputConnection(regionFilter->GetOutputPort());
>>         conMapper->Update();
>> stlActor->SetMapper(conMapper);
>>
>> RenderData(stlActor); //my function for rendering
>>
>>
>>
>> Am 11.04.2013 18:07, schrieb Bill Lorensen:
>>
>> There is a "region growing" filter in VTK.
>> // .NAME vtkPolyDataConnectivityFilter - extract polygonal data based on
>> geomet\
>> ric connectivity
>>
>> // .SECTION Description
>>
>> // vtkPolyDataConnectivityFilter is a filter that extracts cells that
>>
>> // share common points and/or satisfy a scalar threshold
>>
>> // criterion. (Such a group of cells is called a region.) The filter
>>
>> // works in one of six ways: 1) extract the largest (most points)
>> connected reg\
>> ion
>>
>> // in the dataset; 2) extract specified region numbers; 3) extract all
>>
>> // regions sharing specified point ids; 4) extract all regions sharing
>>
>> // specified cell ids; 5) extract the region closest to the specified
>>
>> // point; or 6) extract all regions (used to color regions).
>>
>> //
>>
>>
>>
>>
>>  On Thu, Apr 11, 2013 at 11:13 AM, Marc Huber <marchuber.hft at gmx.de>wrote:
>>
>>>  i want to divide objects into polygons (regions) which point in a very
>>> similiar direction.
>>>
>>> I have computed normal vectors for the points of the object.
>>> now i want to extend a method of image processing to 3D.
>>> in an image i'm growing regions with similar color values starting from
>>> different seed points.
>>> this i want to apply in a changed way to the 3D space
>>> my normal vectors are my "color values" and I want to iterate through
>>> the 3D space to grow regions.
>>>
>>> if i have no regular spacing between the points i might get problems
>>>
>>>
>>>
>>> Am 11.04.2013 16:44, schrieb Bill Lorensen:
>>>
>>> You could create a volume of distances to the triangles. The distance
>>> field will have regular spacing in x,y,z but the x,y,z value will be
>>> distance to the surface.
>>>
>>>  Are you trying to compute something? Maybe if we know what the final
>>> problem is we can provide some ideas.
>>>
>>>
>>>
>>> On Thu, Apr 11, 2013 at 8:54 AM, Marc Huber <marchuber.hft at gmx.de>wrote:
>>>
>>>>  unfortunatelly not. I need it and hoped that vtk is able to do this.
>>>> I have to iterate through point clouds with a regular spacing like
>>>> iterating through pixels of an image. So in fact I don't even need te
>>>> visualization, just the point cloud extracted from the visualization.
>>>>
>>>> thanks for your help
>>>>
>>>> Best regards
>>>> Marc
>>>>
>>>>
>>>> *Gesendet:* Donnerstag, 11. April 2013 um 14:45 Uhr
>>>>
>>>> *Von:* "Bill Lorensen" <bill.lorensen at gmail.com>
>>>> *An:* "Marc Huber" <marchuber.hft at gmx.de>
>>>> *Cc:* "VTK Users" <vtkusers at vtk.org>
>>>>  *Betreff:* Re: Re: [vtkusers] TIN to regular mesh
>>>>   I don't know of a vtk filter that does this.
>>>>
>>>> Do you have a reference for an algorithm that does this?
>>>>
>>>>
>>>> On Thu, Apr 11, 2013 at 8:43 AM, Marc Huber <marchuber.hft at gmx.de>wrote:
>>>>>
>>>>>
>>>>> Sorry for leaving so much unclear.
>>>>> I have closed volumes e.g. a CAD model of a pipe
>>>>>
>>>>> Best regards
>>>>> Marc Huber
>>>>>
>>>>>
>>>>> *Gesendet:* Donnerstag, 11. April 2013 um 14:22 Uhr
>>>>> *Von:* "Bill Lorensen" <bill.lorensen at gmail.com>
>>>>> *An:* "Marc Huber" <marchuber.hft at gmx.de>
>>>>> *Cc:* "VTK Users" <vtkusers at vtk.org>
>>>>> *Betreff:* Re: [vtkusers] TIN to regular mesh
>>>>>   What source of object is being modeled? Is it a closed volume? An
>>>>> elevation map?
>>>>>
>>>>> On Thu, Apr 11, 2013 at 2:09 AM, Marc Huber <marchuber.hft at gmx.de>wrote:
>>>>>>
>>>>>>  I need a quad mesh where the point distance in x and y direction is
>>>>>> always the same.
>>>>>>
>>>>>> Best regards
>>>>>> Marc
>>>>>>
>>>>>>
>>>>>> Am 10.04.2013 um 21:52 schrieb Bill Lorensen <bill.lorensen at gmail.com
>>>>>> >:
>>>>>>
>>>>>>
>>>>>>  What is your definition of "regular mesh"? A regular triangular
>>>>>> mesh is one where each element has 3 edges and the valence of each interior
>>>>>> point is 6. A regular quad mesh is one where each element has 4 edges and
>>>>>> the valens of interior points is 4.
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Apr 10, 2013 at 11:50 AM, Marc Huber <marchuber.hft at gmx.de>wrote:
>>>>>>>
>>>>>>>   Hi,
>>>>>>>
>>>>>>> I have a CAD model, which is triangulated. What I'd like to do is to
>>>>>>> create a regular mesh of it.
>>>>>>> I already searched in the archives and found out that it might help
>>>>>>> to use shepard. I awfully don't get it managed to solve this problem. Maybe
>>>>>>> I’m also just searching with the wrong keywords.
>>>>>>> Has maybe somebody some example code for this? (if c++, tcl,
>>>>>>> python,... doesn't matter)
>>>>>>>
>>>>>>> I'd be very thankful if anybody could help me.
>>>>>>>
>>>>>>>  Best regards
>>>>>>> Marc
>>>>>>>
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>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Unpaid intern in BillsBasement at noware dot com
>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>> Unpaid intern in BillsBasement at noware dot com
>>>>>
>>>>
>>>>
>>>> --
>>>> Unpaid intern in BillsBasement at noware dot com
>>>>
>>>
>>>
>>>
>>>  --
>>> Unpaid intern in BillsBasement at noware dot com
>>>
>>>
>>>
>>>   --
>>> Best regards / Mit freundlichen Grüßen
>>> Marc Huber
>>>
>>>
>>
>>
>>  --
>> Unpaid intern in BillsBasement at noware dot com
>>
>>
>>
>> --
>> Best regards / Mit freundlichen Grüßen
>> Marc Huber
>>
>>
>
>
> --
> Unpaid intern in BillsBasement at noware dot com
>



-- 
Unpaid intern in BillsBasement at noware dot com
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