[vtkusers] normals

[Ocean Spring]

if you are working on a mesh. and the normal vector of a triangle facet can
be obtained
by doing a cross product of two edges, right? and if you want the normal
vector
of the vertices of a triangle you can obtain it by interpolating of
surrounding facets or
if you are extract the isosurface from volume data, the normals can be
calculated by
central difference or any finite different methods based on the volume
data.(see Marching cubes algorithm)

there are plenty of research papers addressing this issue. i am not exactly
sure
how VTK could achieve this by calling any function..

good luck

O.S.


On Tue, Oct 25, 2011 at 12:35 AM, andon <antoniod987 at gmail.com> wrote:

> OK, I've understood this....but i need to get out an angle, in particular i
> need to get the orientation of the cell on wich i've extracted the
> normal..do you know ho can i do this???
>
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