Coordinate Systems

[Ana Cugat]

<x-flowed>Yes, you're right. Anyway, my question is not only aboutignoring the 
y-coordinate, etc.. As a matter of fact, I've got polydata obtained from 
cutting a sphere with a plane. I use vtkPolyDataMapper2D to render this cut 
in the viewer, but i cannot manage to control its position or its size. I 
cannot use the image classes because my data is not Image cache data. So if 
I render the cut in the 3D renderWindow, the coordinates are correct, but in 
the 2D image window, 1 pixel corresponds to maybe 10 units or whatever... 
how can I resample or rotate or position my cut? How can I establish a 
relation between the 3D render window and the image window?

Thanks,

Ana


>From: Kerrie Holton Tainter <tainter at stdavids.picker.com>
>Reply-To: tainter at stdavids.picker.com
>To: Ana Cugat <c1f6326 at hotmail.com>
>CC: vtkusers at gsao.med.ge.com
>Subject: Re: Coordinate Systems
>Date: Tue, 12 Oct 1999 12:31:21 -0400
>
>Actually,
>
>I think PolyDataMapper2D projects all the z planes into one "overlay" plane 
>on
>the viewport.  anyway, f you want to ignore the y-coordinate of the 
>polydata,
>you could
>just apply a rotation transform before you map to the overlay plane.
>
>vtkCoordinate seems to describe a location in space, and is useful for 
>changing
>from
>one coordinate system (ie. world coords to display coords).  I don't think 
>it's
>useful
>for making the y-axis correspond to z.
>
>Ana Cugat wrote:
>
> > Hello everybody,
> >
> > I'd like to know how to pass the polydata of the 3D renderer to the 2D
> > viewport. vtkPolyDataMapper2D gets the x, y coordinate of the 3D 
>polydata
> > surface to display the image in the viewport. A vtkCoordinate object can 
>be
> > used to transform the data in other ways, but I don't quite understand 
>how
> > to use it. What should I do if, for instance, I wanted to ignore the
> > y-coordinate?
> >
> > Thanks,
> >
> > Ana
>
>
>
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</x-flowed>