1. Start up Layout and load in "Pistons.lwo". It consists of two parts. The Base and the Shaft. Notice how the objects "Pivotpoints" are set. I made this in Modeler using the "Pivot" tool, just so I could save some time writing this tutorial. Figure 1.

Click HERE for the piston object.

2. We are gonna automate this piston using Inverse Kinematics. And for this we need 4 nullobjects. Two for the Base, and two for the Shaft. Start by adding two nullobjects called "Base_base" and "Base_end". Parent the "Base" layer to "Base_base" null, and parent "Base_end" to "Base" layer. So you have a chain going Base_base -> Base layer -> Base_end. Then move your nulls into position as shown in figure 2.

3. Now repeat the above steps for the "Shaft" layer. Add two nulles called "Shaft_base" and "Shaft_end". Move the nulls into position as in figure 3. Parent the "Shaft" layer to "Shaft_base" and parent "Shaft_end" to the "Shaft" layer. When you perform the parenting actions, you will see the "Shaft" layer jump up as much as you repositioned the null. So move your "Shaft" back down again. You want to have figure 3.

4. Now we are gonna setup the Inverse Kinematics. Select "Base_base" go into the "Motion Options" by pressing "m" on your keyboard.
There you will see two tabs saying "IK and Modifiers" and "Controllers and Limits". Click on the "Controllers and Limits" tab.
Set the "Bank Controller" to "Inverse Kinematics". Leave everything else. Repeat this for "Base" layer and "Base_end". But on "Base_end" after setting the "Bank Controller", switch to the "IK and Modifiers" tab. There you will set the "Goal Object" to "Shaft_base" and enable "Full-time IK". See figure 4.

5. Repeat the exact same process as above, but replace "Base" with "Shaft" and set the "Goal Object" to Base_base".
When that is done, select your "Shaft_base" and move it around in the X/Y axis. Your Base/Shaft objects will follow each other and point towards each other correctly as in figure 5.

There, now you can build that machine with cool looking hydraulics just like you always dreamed of.