[vtkusers] vtkCamera::Elevation(...)

[Matthias Langer]

John Platt wrote:

>Hi Matthias,
>
>Elevation() rotates the camera about the cross product of the negative
>of the direction of projection and the view-up vector centered on the
>focal
>point. Singularities exist at the north & south poles where the view-up
>vector becomes parallel to the view plane normal. This can be avoided by
>orthogonalising the view-up vector after each Elevation() but this flips
>direction at the poles and the camera motion is not continuous. The
>elevation is therefore best restricted to (-90, +90).
>
>HTH
>
>  
>
Thanks very much for your tipp; I thought that the view up vector is 
updated automatically when calling Elevation(...). Following your tipp, 
I wrote a routine which recalculates the the view-up vector after 
Elevation(...), using the last camera position, the focal point and the 
actual camera position. This worked fine and furthermore seems complety 
contineous.
Matthias Langer