Hi Kevin,
Calling the 3D Graph's ControlImage method repeatedly and then looping those as an animation (or converting to an animated GIF) is the only way to capture multiple images from the 3D Graph.
This is another case of a good product suggestion for future development on the 3D Graph. You can visit http://ni.com/contact and click "Product Feedback" to submit a product suggestion for this and any other features you'd like to see.
David Mc.
NI Applications Engineer