[vtkusers] TIN to regular mesh

[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
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