[vtkusers] TIN to regular mesh

Bill Lorensen bill.lorensen at gmail.com
Fri Apr 12 08:33:17 EDT 2013 

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
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