[vtkusers] vtkCamera as X-Ray camera

[David Gobbi]

Props can be anywhere.  But if you want them to be visible, they must lie
between the near clipping plane and the far clipping plane, which are set
with camera->SetClippingRange(double dNear, double dFar).  These are set as
distances from your camera position.  In order for things to be visible,
they must be at least "dNear" distance from the camera, and must not be
further than "dFar" distance from the camera.

"Position" is always the camera position in world coordinates.

"FocalPoint" must lie between the green point and the purple point that are
shown on your diagram. I recommend that it be within the grey blob (i.e.
within the "patient").

And of course I highly recommend that you set the ClippingRange as well.
 The dNear can be set to half of the distance from the camera position to
the focal point, and the dFar should be set to the distance from the camera
position to the detector.



On Wed, Apr 17, 2013 at 3:27 PM, Taylor Braun-Jones
<taylor at braun-jones.org>wrote:

> Hello vtkusers,
>
> I'm trying to position and orient a vtkCamera to model an X-Ray camera as
> shown in the figure below.
>
> [image: Inline image 1]
>
> I'm running into uses so I just want to make sure this is fundamentally
> possible with a vtkCamera. I know:
>
>  - Position and orientation of the camera coordinate system (red axes) in
> world space
>  - X-Ray point source (green point)
>  - Principal point (purple point)
>  - The width, d, of the square detector (and therefore the view angle)
>
> (1) Can I place Props between the camera Position and FocalPoint?
>
> (1a) If so, how should the Position and FocalPoint be set?
>
> (1a) If not, is there another approach to set the
> Position/FocalPoint/ViewUp to simulate this?
>
> Thanks!
> Taylor
>
>
>
>
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