[vtkusers] Setting Camera/Focal Point Orientation

[Andrew Maclean]

Hi Michael,

I think the simplest explanation is that these values are compounded into
the homogenous matrix that directly specifies the orientation. As such
because the homogenous matrix is the product of one or all of these values
plus any other orientation/rotation/translation values it will never be
possible, except in very simple single parameter cases, to extract out the
entered values from the homogenous matrix.

In general it is very difficult because of angle ambuguities and also
because the rotation axis may not be coincident with the cartesian axes to
extract these values.


Andrew





On 10/16/06, Michael Rice <marice at knology.net> wrote:
>
> After looking at the vtkCamera, I see there are methods to adjust the
> Elevation, Azimuth, Roll, Yaw, and Pitch. These appear to function as
> offsets from the current value, but I don't see functions to get
> these values - other than Roll. Also, there is a SetRoll function to
> set the absolute roll value, but there aren't functions to set the
> absolute angles for the other values.
>
> I guess I have 2 questions:
>
> 1. Why aren't there functions to get/set the absolute values for
> elevation, azimuth, yaw, and pitch?
>
> 2. Are there other VTK methods or sample code that returns these values?
>
> Thanks.
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-- 

___________________________________________
Andrew J. P. Maclean
Centre for Autonomous Systems
The Rose Street Building J04
The University of Sydney  2006  NSW
AUSTRALIA
Ph: +61 2 9351 3283
Fax: +61 2 9351 7474
URL: http://www.cas.edu.au/
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