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

[Elvis Stansvik]

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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