[vtkusers] Actors in front of camera clipped despite ResetCameraClippingRange()

Elvis Stansvik elvis.stansvik at orexplore.com
Tue Jun 21 07:20:10 EDT 2016

I'm attaching the full code for brevity, but the relevant parts are how I'm
treating the camera in my CylindricalInteractionStyle class and the if
__name__ == '__main__' block.


2016-06-21 13:06 GMT+02:00 Elvis Stansvik <elvis.stansvik at orexplore.com>:

> Hi all,
> I have a setup where the camera always moves on a cylinder of radius 3.0
> around my subject (just testing with a stack of cones at the moment). The
> focal point is always positioned along the Y axis, and the camera may be
> moved up and down independent of the focus point, but the camera is always
> at a distance of 3 from the Y axis.
> As soon as the user moves the camera, I reset the camera clipping range
> with ResetCameraClippingRange(). Despite this, when the camera and the
> focal point are far away from eachother, the actors (my stack of cones) get
> clipped by the near plane for some reason.
> See the attached screenshot which shows the clipping.
> What I'm doing to my camera (in response to Shift+mouse drag in my custom
> interactor) to end up in this situation is just:
>         camera = renderer.GetActiveCamera()
>         (x, y, z) = camera.GetPosition()
>         camera.SetPosition(x, y - self.PanningFactor * dy, z)
>         renderer.ResetCameraClippingRange()
> and I've verified that the camera is always at a distance of 3.0 from the
> Y axis.
> The cones I'm using in this test were created with:
>     for i in range(-10, 20):
>         coneSource = vtkConeSource()
>         coneSource.SetDirection(0, 1, 0)
>         coneSource.SetResolution(8)
>         coneSource.SetCenter(0, i, 0)
>         coneMapper = vtkPolyDataMapper()
>         coneMapper.SetInputConnection(coneSource.GetOutputPort())
>         coneActor = vtkActor()
>         coneActor.SetMapper(coneMapper)
>         widget.renderer.AddActor(coneActor)
> I don't understand why I see clipping occur here, since I'm using
> ResetCameraClippingRange, and nothing is behind the camera. The radius of
> these cones is the default (0.5).
> It's probably something stupid, but any advice is much appreciated.
> Elvis
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