[vtkusers] Question about normal calc in vtkContourFilter

[Lorensen, William E (CRD)]

If you use Marching Cubes, the normals arfe calculated using central differences. Otherwise, you'll
need to run the PolyDataNormals filter.


-----Original Message-----
From: Adam D. Burry [mailto:aburry at igotechnologies.com]
Sent: Tuesday, December 04, 2001 2:04 PM
To: Weiguang Guan; vtkusers at public.kitware.com
Subject: Re: [vtkusers] Question about normal calc in vtkContourFilter


Weiguang:

> Does anyone know how to use vtkContourFilter to get a surface so that each
> vertex of the mesh has not only coordinates but normal as well? I look at
> the manual and cannot figure out what should be passed in to
>                     SetComputeNormals (int)
> Another question is how the normals are calculated, are they determined by
> vertices' coordinates? Can I use gradient instead of normal in lighting
> computation? Any hint will be appreciated, better with sample code.

I can't answer all of this question, but I think I can answer part of
it. If you have a surface with missing normals you need to use the
vtkPolyDataNormals filter.

Adam

--
Mr. Adam D. Burry, Software Developer
aburry at igotechnologies.com
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