Shater is based on real world physics. Just animate the force position or strength to make the effect start where you want it to start. There are a zillion questions about shatter on this and other forums and they always are answered correctly by asking you do animate the force.
Thanks for the reply.
I've tried animting the force. Well I tried animating the forces and gravity (otherwise it dropped) but that didn't help. The text just stayed static when the force and gravity were brought up. Sorry - I should've said that in the first post.
Um, there are more controls in Shatter than just Force. Play around with them. See how they work. Learn.
You want to animate force one. Set the size to zero, then to one. Or move it into the text. Set a couple keyframes and you're done. I don't mean to sound impatient, but this isn't hard. There are 8 million shatter tutorials on the web that show you exactly how to do this. The wireframe view shows you exactly where the force field that breaks apart the layer is in 3D space. You can add a comp camera, select comp camera in the view options, then move around to see what you're doing.
Animate the radius, the depth, or the strength. This screenshot shows a text layer from the back with the force set to a depth of .09 and a radius set to .26. You can see the force pushing the bricks out.