This top post contains the most recent version of RE:Lay, Blender's inheritance effector. I have revised the code for 2.66 (left 2.65 available as well). RE:Lay now runs via the frame_change_pre handler instead of the rotating empty with a driver. This revisions eases the workflow as well. Prior to this release there was a sampling button and you were forced to re-sample the main animation each time you revised it. This slowed down workflow and added confusion when the source animation fell out of synch with the sampled animation. Sampling and baking have been removed.
Now RE:Lay simply samples the f-curves directly for the object that it is applied to on-the-fly.
Because of this new approach, it is now possible to sample the past and future portions of the f-curve. Thus negative offsets are now valid so target object can actually precede the source object animation wise.
New support for DATA based f-curves. What does this mean?
Previously RE:Lay only relayed LOC/ROT/SCALE. Now it will attempt to relay any animated parameter to a target object. Say you have a font object that moves around in space. That is an OBJECT based action. Say you also have the font object extruding over time. That is a DATA based action. RE:Lay will now attempt to transfer OBJECT and DATA actions to the target. If the target has a matching data parameter the data will be relayed. Continuing with our font example, an extrude relayed to a mesh has no effect, but an extrude relayed to a curve or font would.
Give it a try.
I am leaving the old tutorial video up. Most of the instructions are still valid. Simply ignore the sampling portion, you no longer need to do this.
Here is a tutorial that show how to use it.
I have often seen posts about how to use one objects animation in a delayed fashion to cause another object to move in the same way. That is what RE:Lay does. It relays the animation applied to the relay object to any targets that are in the list. Each target has an offset and time stretch parameter as well. So you can make the relayed animation lag behind and even slower (not faster yet).
RE:Lay manipulates the DELTA portion of the target object. This means you can still animate the target and get a dual style animation out of it. Also, because it only affects the DELTAs you can use the manipulator to re-position the object after it has been targeted if it has no keyframes.
Run or Install the AddOn.
Move your mouse into the 3D window and press SHIFT-A
Choose RE:Lay Offset Animator from the list.
Select an object and click the rename with relay button, under the object context. Animate the relay object. Any object named with the prefix will have a new targeting panel under it's object properties. Add targets and play with offsets and axis mapping.
Or just download the BLEND file and press play.