This may not be helpful to you, but if you have Adobe AfterEffects, there's an effect called Shatter that is used for exactly what you're talking about. Otherwise, I'd suggest trying to build your individual pieces of glass in one of the modelers (maybe the spline would be easiest for fitting the pieces precisely together). Then, place the glass peices together horizontally. Position your camera below the glass looking up, and use a directional force to break the pieces apart, flying toward the camera. (You'd have to enable physics.) I hope this is helpful. - Dex