vtk3DWidget

Section: Visualization Toolkit Widget Classes

Usage

vtk3DWidget is an abstract superclass for 3D interactor observers. These 3D widgets represent themselves in the scene, and have special callbacks associated with them that allows interactive manipulation of the widget. Inparticular, the difference between a vtk3DWidget and its abstract superclass vtkInteractorObserver is that vtk3DWidgets are "placed" in 3D space. vtkInteractorObservers have no notion of where they are placed, and may not exist in 3D space at all. 3D widgets also provide auxiliary functions like producing a transformation, creating polydata (for seeding streamlines, probes, etc.) or creating implicit functions. See the concrete subclasses for particulars.

Typically the widget is used by specifying a vtkProp3D or VTK dataset as input, and then invoking the "On" method to activate it. (You can also specify a bounding box to help position the widget.) Prior to invoking the On() method, the user may also wish to use the PlaceWidget() to initially position it. The 'i' (for "interactor") keypresses also can be used to turn the widgets on and off (methods exist to change the key value and enable keypress activiation). To support interactive manipulation of objects, this class (and subclasses) invoke the events StartInteractionEvent, InteractionEvent, and EndInteractionEvent. These events are invoked when the vtk3DWidget enters a state where rapid response is desired: mouse motion, etc. The events can be used, for example, to set the desired update frame rate (StartInteractionEvent), operate on the vtkProp3D or other object (InteractionEvent), and set the desired frame rate back to normal values (EndInteractionEvent).

Note that the Priority attribute inherited from vtkInteractorObserver has a new default value which is now 0.5 so that all 3D widgets have a higher priority than the usual interactor styles.

To create an instance of class vtk3DWidget, simply invoke its constructor as follows

  obj = vtk3DWidget

Methods

The class vtk3DWidget has several methods that can be used. They are listed below. Note that the documentation is translated automatically from the VTK sources, and may not be completely intelligible. When in doubt, consult the VTK website. In the methods listed below, obj is an instance of the vtk3DWidget class.