Perspective vs parallel projection

[Lisa S. Avila]

Hi Paul,

It is possible to make things on the focal plane be the same size in
perspective as they would be in parallel, but off course things off the
focal plane vary in size based on distance in perspective, and don't do
that in parallel. Also, when interacting in parallel, the camera does not
move - so when you switch back to perspective you are back where you were.
You would not want the camera to move in parallel since it would start
clipping into objects which would seem strange.

Lisa


At 09:48 AM 8/23/99 -0700, Paul Hsieh wrote:
>Hi all:
>
>Is there a way to "synchronize" the perspective and parallel projections
>when it comes to zooming and dollying?
>
>When I switch from perspective projection to parallel projection
>(by invoking vtkCamera::SetParallelProjectionOn()), then zoom the view,
>and then switch back to perspective projection, the actors in the
>perspective projection are not zoomed. 
>
>Looking at the source code, I see that zooming is done differently
>for perspective and parallel projection. Is there a way to calculate
>and set some camera parameters (for example, parallelScale) so that the
>actors are about the same size in parallel versus perspective projection?
>
>Or is this an ill defined problem?
>
>Thanks.
>Paul
>
>
>-----------------------------------------------------------------------------
>This is the private VTK discussion list.  Please keep messages on-topic.
>Check the FAQ at: <http://www.automatrix.com/cgi-bin/vtkfaq>
>To UNSUBSCRIBE, send message body containing "unsubscribe vtkusers" to
><majordomo at gsao.med.ge.com>.  For help, send message body containing
>"info vtkusers" to the same address.     Live long and prosper.
>-----------------------------------------------------------------------------
> 



-----------------------------------------------------------------------------
This is the private VTK discussion list.  Please keep messages on-topic.
Check the FAQ at: <http://www.automatrix.com/cgi-bin/vtkfaq>
To UNSUBSCRIBE, send message body containing "unsubscribe vtkusers" to
<majordomo at gsao.med.ge.com>.  For help, send message body containing
"info vtkusers" to the same address.     Live long and prosper.
-----------------------------------------------------------------------------