[vtkusers] rotating vtkCamera

Marc Cotran marc at cotran.ca
Thu Apr 19 12:41:36 EDT 2007


Hi other Mark :)

Try calling vtkCamera::OrthogonalizeViewUp() after each call to 
Elevation(). Although the VTK docs say:

"Recompute the ViewUp vector to force it to be perpendicular to 
camera->focalpoint vector. Unless you are going to use Yaw or Azimuth on 
the camera, there is no need to do this."

I would try it anyway :)

Marc

Mark Wyszomierski wrote:
> Hi Marc,
>
> Elevation seems to work - kind of. I keep calling elevate with the
> amount of degrees I want to change by:
>
>     for (int i = 0; i < 64; i++) {
>        pCamera->Elevation(360.0 / 64.0);
>     }
>
> It works fine through about a 90 degree rotation - but then I start
> getting debug error messages about the view up having to be
> recalculated, and the volume starts spinning around out of control!
>
> Thanks,
> Mark
>
> On 4/19/07, Marc Cotran <marc at cotran.ca> wrote:
>> Hi there,
>>
>> Try vtkCamera::Elevation() and Azimuth() - both methods take an angle
>> parameter. Sounds like you are looking for Elevation(). Pitch(), on the
>> other hand, changes the focal point, not the camera position.
>>
>> hth
>>
>> Marc
>>
>>
>> Mark Wyszomierski wrote:
>> > Hi,
>> >
>> > Is there a method of vtkCamera to rotate about the focal point?
>> > Something like:
>> >
>> > for (int i = 0; i < 64; i++) {
>> >     double dPitch = i * (360.0 / 64);
>> >     pCamera->Pitch(dPitch);
>> >     // render..
>> > }
>> >
>> > The effect I'm looking for is to have the camera orbit around its
>> > focal point in the direction of its view up.
>> >
>> > Thanks,
>> > Mark
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>>





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