Mesh Warping in Shake
So, the elusive mesh warper... many other packages have one, but until that day when a warper is released, you still have a few options.
Idisplace is your friend. If you have a subtle change to be made, you might get by with a strategically placed ramp sent into idisplace. The brighter areas will push or pull (X or Y depending on your settings) and the dark areas will remain unchanged. So displace, big deal. How do I mesh warp?
If you want to make more dynamic changes, the process is exactly the same. The key is making a good displacement map to send to the Idisplace. Use the red channel for X motion. Positive red is right, negative red values move the object to the left (yay float!), and zero is no change. The green channel will do the exact same thing, but for Y.
Take a grad node, and send it through a tile node... set the tiling ot be 5x5. Check out the red channel. Put a little blur on that and send this to your Idisplace. Connect red to X and green to Y. getting cooler... Seeing a pattern here?
What if each corner of each tile was a pin, and as you pulled that pin in X the value of Red for that area would incresae or decrease, thus driving your Idisplace and warping the image? Using expressions you can link all of these corners together, so they work together... for the common good. The result is a mesh warper. You can grab yours here today!
Enjoy! - The Meticulous Effects Kids.