//Default position of the viewer.
us.getViewingPlatform().setNominalViewingTransform();
//The following three lines enable navigation through the scene using the mouse.
OrbitBehavior ob = new OrbitBehavior(meuCanvas3D, OrbitBehavior.REVERSE_ALL);
BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0), 100.0);
ob.setSchedulingBounds(bounds);
us.getViewingPlatform().setViewPlatformBehavior(ob);
us.addBranchGraph(cena);
//Show the canvas/window.