about LineWidget?

Sorry, I don’t know how to use ‘resolveCoincidentTopology’ Can you provide more hints.

I will add vtkImageData to the volume and add the volume to scene.renderer.
Then
scene. widgetManager. setRenderer (scene. renderer);
… Initialize widgets, such as LineWidget, RectangleWidget, etc

I use the following code to ensure that they are on the same plane, for example:
const camera = scene.renderer.getActiveCamera();
const manipulator = scene.widgets.rectangleWidget.getManipulator();
manipulator.setUserOrigin(…camera.getFocalPoint());
manipulator.setUserNormal(…camera.getDirectionOfProjection());

I don’t know if this is enough