[changeset] surface normals

[Kai Habel]

Kai Habel schrieb:
> Hello,
>
> the attached changeset adds the calculation of normals for surface
> boundaries. For the calculation of interior normals four additional
> neighbors are being used.
>
> Kai
>   
Just a quick comment on the change below

+              double d = - std::max(std::max(fabs(nx), fabs(ny)), fabs(nz));
+              //double d = - sqrt (nx*nx + ny*ny + nz*nz);

It seems matlab calculates the normal vector in manner that the largest element is set to 1.0. We have set the length to 1.0 previously. I think the reason is to make the vector more human readable like 

> v=[1 -0.5 0.25]
v =

   1.00000  -0.50000   0.25000


versus

> v/norm(v)
ans =

   0.87287  -0.43644   0.21822

>

Kai