Center a volume in 3D scene

Development
1

Hi, I want to center a certain volume in the 3D view. I tried
layoutManager = slicer.app.layoutManager()
threeDWidget = layoutManager.threeDWidget(0)
threeDView = threeDWidget.threeDView()
threeDView.resetFocalPoint()
in the scripted repository, but I have more than one nodes in the scene and I don’t want to delete them, so it doesn’t work. Does anyone have any idea how to do this?

Thanks for your time!

2

You don’t need to delete the nodes that you don’t want to include in the center computation, just temporarily hide them (node.GetDisplayNode().SetVisibility(False)).

3

Hi Andras,
Thanks for your answer! I tried hiding them but it is still not at the center on the scene.
If I have more than one volumes, even if I hide the others, the volume still won’t be at the center on the scene.
What I want to know is how to center one specific volume while other volumes are still there.
Thanks!

4

You can center the camera on a node by basic VTK method calls. Something like this should work:

node = getNode('CTChest')
threedView = slicer.app.layoutManager().threeDWidget(0).threeDView()

# Get volume center
bounds=[0,0,0,0,0,0]
node.GetRASBounds(bounds)
nodeCenter = [(bounds[0]+bounds[1])/2, (bounds[2]+bounds[3])/2, (bounds[4]+bounds[5])/2]

# Shift camera to look at the new focal point
renderWindow = threedView.renderWindow()
renderer = renderWindow.GetRenderers().GetFirstRenderer()
camera = renderer.GetActiveCamera()
oldFocalPoint = camera.GetFocalPoint()
oldPosition = camera.GetPosition()
cameraOffset = [nodeCenter[0]-oldFocalPoint[0], nodeCenter[1]-oldFocalPoint[1], nodeCenter[2]-oldFocalPoint[2]]
camera.SetFocalPoint(nodeCenter)
camera.SetPosition(oldPosition[0]+cameraOffset[0], oldPosition[1]+cameraOffset[1], oldPosition[2]+cameraOffset[2])
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