[vtkusers] Triangulate surface points?

[Cory Quammen]

Cool, thanks!.

On Fri, Mar 25, 2016 at 9:48 AM, Andras Lasso <lasso at queensu.ca> wrote:

> It can generate non-convex surfaces up to some point - check out the
> video and/or try it yourself (you can install the Volume clip extension in
> Slicer by two clicks and you can mark points and drag them around to see
> how the surface is evolving). The alpha parameter in Delaunay 3D controls
> handling of concavities. Limitations include that a non-zero alpha may make
> the triangulation to fail and irregular point distances may confuse the
> smoothing algorithm.
>
>
>
> Andras
>
>
>
> *From: *Cory Quammen <cory.quammen at kitware.com>
> *Sent: *March 25, 2016 09:37
> *To: *Andras Lasso <lasso at queensu.ca>
> *Cc: *Philip Fackler <philip.fackler at gmail.com>; vtkusers at vtk.org
>
> *Subject: *Re: [vtkusers] Triangulate surface points?
>
>
> Andras,
>
> That's a good idea as well, but doesn't vtkDelaunay3D produce a convex
> hull of the input points? That's fine if your object is convex, of course,
> but may not give you the expected results if your object has a concave
> region.
>
> If there is a feature in vtkDelaunay3D that can produce concave surfaces,
> I would be interested to know about it.
>
> Thanks,
> Cory
>
> On Fri, Mar 25, 2016 at 8:34 AM, Andras Lasso <lasso at queensu.ca> wrote:
>
>> We get excellent results for sparse point sets using a combination of
>> vtkDelaunay3D, vtkDataSetSurfaceFilter, and vtkButterflySubdivisionFilter.
>> The generated surface includes the exact points that we specify.
>>
>>
>>
>> You can see what kind of surfaces you can generate from a small number of
>> points:
>>
>> https://www.youtube.com/watch?v=1mYNwJbE7dQ
>>
>>
>>
>> You can play with it if you download 3D Slicer and install Volume Clip
>> extension (
>> https://www.slicer.org/slicerWiki/index.php/Documentation/Nightly/Extensions/VolumeClip).
>> Source code is available here:
>>
>>
>> https://subversion.assembla.com/svn/slicerrt/trunk/VolumeClip/src/VolumeClipWithModel/
>>
>> (relevant part is in updateModelFromMarkup function)
>>
>>
>>
>> Andras
>>
>>
>>
>> *From:* vtkusers [mailto:vtkusers-bounces at vtk.org] *On Behalf Of *Cory
>> Quammen
>> *Sent:* March 24, 2016 2:29 PM
>> *To:* Philip Fackler <philip.fackler at gmail.com>
>> *Cc:* vtkusers at vtk.org
>> *Subject:* Re: [vtkusers] Triangulate surface points?
>>
>>
>>
>> Philip,
>>
>>
>>
>> Please take a look at
>>
>>
>>
>>
>> http://www.vtk.org/doc/nightly/html/classvtkSurfaceReconstructionFilter.html
>>
>>
>>
>> and
>>
>>
>>
>> http://www.vtkjournal.org/browse/publication/718
>>
>>
>>
>> I don't have direct experience with these classes, but they may have what
>> you need.
>>
>>
>>
>> HTH,
>>
>> Cory
>>
>>
>>
>> On Thu, Mar 24, 2016 at 2:24 PM, Philip Fackler <philip.fackler at gmail.com>
>> wrote:
>>
>> If someone could even definitively tell me "no, you can't do this" that
>> would be helpful.
>>
>>
>>
>> Thanks,
>>
>> Philip Fackler
>>
>>
>>
>> On Wed, Mar 16, 2016 at 6:24 PM Philip Fackler <philip.fackler at gmail.com>
>> wrote:
>>
>> Is there a way to triangulate a set of surface points using vtk? I've
>> looked around and everything I've found (vtk, cgal, pcl) only do a surface
>> reconstruction which ends up generating its own points to triangulate. I
>> want to actually use the points I have as the vertices of the
>> triangulation. Along with the point locations, I have a lot of information
>> available in my code that I could provide:
>>
>>
>> Normal vector at each point
>>
>> Bounding segmented curve(s) (i.e., lists of edge cells indexing the list
>> of surface points)
>>
>> A polydata representation of the surface (Note that the points I want to
>> triangulate are distinct from the points involved in this)
>>
>> The only vtk utility that seems to come close to this is vtkDelaunay2D,
>> but it's only useful if all the points can be mapped to a 2D plane. This
>> isn't possible in general without a parametric surface, which is one bit of
>> information I don't have.
>>
>> Thanks in advance for the help.
>>
>>
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>>
>>
>>
>> --
>>
>> Cory Quammen
>> R&D Engineer
>> Kitware, Inc.
>>
>
>
>
> --
> Cory Quammen
> R&D Engineer
> Kitware, Inc.
>



-- 
Cory Quammen
R&D Engineer
Kitware, Inc.
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