[vtkusers] function to calculate the angle between three points

[David Doria]

On Tue, Jan 12, 2010 at 2:47 PM,  <lynx.abraxas at freenet.de> wrote:
> Hello again!
>
>
> I fear I could have asked unclearly so I give it another try:
> Is there a filter in vtk that calculates the angle of an array containing many
> tupels of two points/vectors? The angle I want is  the  one  between  the  two
> point-vectors and the origin.
> Or  would  there  be  an optimzed function to calculate an angle between three
> points?
> Is there a quicker way to calculate the angle than by normalizing each one and
> taking the arccos of the scalar product?
>
>
> Thanks for any help or hints
> Lynx
>
>
> On 11/01/10 00:12:26, lynx.abraxas at freenet.de wrote:
>> Hello!
>>
>>
>> One other problem I have:
>> How  can  I  calculate  the  angle  of  an edge (eg. the angle between the two
>> points/vertices of a mesh and the origin of the coordinate system)?
>> I want to do that for a complete mesh. Sadly vtkMeshQuality has  no  qualities
>> for  edges.  Is  there any other class in vtk to use or would I have to do the
>> calculation on my own?
>>
>> Thanks again for any help or hints.
>> Lynx
>>
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All -

It may be helpful in cases like this for some of the experienced
members to give a "not that I've seen/heard of" type of response. A
few negative responses from some experienced members can be very
useful to decide if he should go ahead and write something himself.
What I'm imagining is happening if people don't know the answer, they
are just not responding in hopes that someone else will know the
answer and respond. However, sometimes the answer is "no one knows the
answer/ such a filter does not exist" and this can be inferred by a
few "I don't knows".

It's a fine line though I guess, too many "I don't knows" could
generate a lot of noise...

Thanks,

David