[Insight-users] QuadEdgeMeshNormalFilter - Outwards or inwards

[Oscar Esteban]

Dear Jon, Arnaud,

Thanks a lot for your answers, and sorry that I missed your answers for a
long while.

I didn't try to visualize it (never managed to write vectors on vtk
polydata, probably is very easy but I must admit I've been rather sloppy
regarding that).

What Arnaud commented makes a lot of sense. On my case, I empirically check
the direction and they are inwards. But probably, it'd be much faster and
reliable if I checked the order of triangles as Arnaud suggested.

Thanks a lot

Best,
Oscar Esteban


*______________________________________*
*Oscar Esteban*
PhD Student / Researcher

Biomedical Image Technologies (BIT), UPM
ETSI Telecomunicación Lab. C203, Av. Complutense s/n - E-28040 Madrid
(Spain)
+34 915 495 700 ext.4234

Signal Processing Laboratory (LTS5), EPFL-STI-IEL-LTS5
ELD 224 (Bâtiment ELD), Station 11, CH-1015 Lausanne, Switzerland


On 1 October 2013 01:05, Arnaud Gelas <arnaudgelas at gmail.com> wrote:

> Dear Oscar,
>
> You can't know in advance if it is pointing inward or outward.
> One itk::QuadEdgeMesh is oriented, and so the orientation of the normal
> depends on the order triangles are filled in, then AFAIR the orientation is
> then counterclockwise.
>
> HTH
>
>
> On Tue, Oct 1, 2013 at 9:54 AM, Jon Haitz Legarreta <
> jhlegarreta at vicomtech.org> wrote:
>
>> Dear Óscar,
>> although I haven't tried the filter, I would dare to say that it should
>> point outwards if done according to the "normal vector" definition.
>> Were you able to visualize it? May be with VTK or writing the output and
>> using Paraview?
>>
>> It would be nice if you shared what it gives by default.
>>
>> Kind regards,
>> JON HAITZ
>>
>>
>>
>> On 22 June 2013 13:13, Oscar Esteban <oesteban at die.upm.es> wrote:
>>
>>> Dear ITK experts,
>>>
>>> When computing the normals of a closed surface, the resulting vectors
>>> are inwards or outwards?
>>>
>>> I'm trying to figure it out from code but I didn't get it. I also looked
>>> in the software guide and the documentation.
>>>
>>> Best,
>>> Oscar
>>>
>>>
>>> *______________________________________*
>>> *Oscar Esteban*
>>> PhD Student / Researcher
>>>
>>> Biomedical Image Technologies (BIT), UPM
>>> ETSI Telecomunicación Lab. C203, Av. Complutense s/n - E-28040 Madrid
>>> (Spain)
>>> +34 915 495 700 ext.4234
>>>
>>> Signal Processing Laboratory (LTS5), EPFL-STI-IEL-LTS5
>>> ELD 224 (Bâtiment ELD), Station 11, CH-1015 Lausanne, Switzerland
>>>
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