Ziosoft showcased this amazing 3D visualization on iPhone. It is fast and smooth with very high image resolution. With dual touch, seem like it is very easy to control zoom, move cutoff plane, rotate and move object, and select depth of rendering.
From their description and the look, it is obvious that there is web server doing the rendering behind. iPhone seem to provide the dual touch and navigation. Still the the speed is impressive. Either the iPhone has very high speed internet access, or there is some very efficient decompress and rendering algorithms running on it so that data transfer rate is not too high.