Instance Along Curve

This entry covers the concept of duplicating a mesh (cube in this example) along the path of a curve.  This is a very useful animation ability when trying to grow a curvey line or path.  

To start off you'll need at add [SHIFT+A] a curve and a mesh (cube).  It is worth noting that the direction of the curve matters for this example.  To have the cube follow the path of the curve directly, you'll want to situate it at the beginning (curve arrows are pointing away from cube) of the curve.

With the Cube selected, go to the Constraints tab, and set the Target to be the curve you created.

Now select the curve and click on the Curve tab.  In this view, check the box that says Follow.  This is optional, but causes the cube to rotate it's orientation based on the orientation of the curve.  Also, the Frames slider in this view can affect how many frames the duplication will take to cover the entire curve.

Now select the cube once again, and click on the Object tab (gold cube icon).  In this view, set the Parent to be the curve.  Then under the Duplication panel, click the Frames button.  You'll notice now that if you slide the End slider, the cubes will duplicate along the curve.

If you left the Frames value on the Curve's Path Animation to be 100, in this view it should take 100 frames to cover the entire curve with cubes.

Changing the Off slider to a non-zero value will reduce the number of instances that are created along the path, as shown below (offset = 3).

You can now Keyframe [i] the End slider to animate the growth animation.