How to animate multiple lines

Question

I wonder what would be the best way of animating multiple 2 dimensional lines in blender.

Lets say I have lots of line, that are parallel and have some sort of rule, kind of like a PCB board with hundreds of circuits.

The starting frame would be when nothing is visible and during the animation the lines would slowly build up from nothing all the way to the end forming the finished lines.

I have a couple of ideas that might work, but all include heavy hand animation, like:

• grease pencil animation, drawing them one by one, converting to curve, then build up modifier
• some dynamic paint hack

There maybe other more efficient methods that I don't know of and if so, please let me know.

Answer 1

You can use Curves and animate the Start bevel and End Bevel factors:

These options determine where to start the Bevel operation on the Curve being beveled. Increasing the Start Bevel Factor to 0.5 will start beveling the Curve 50% of the distance from the start of the Curve (in effect shortening the Curve). Decreasing the End Bevel Factor by 0.25 will start beveling the Curve 25% of the distance from the end of the Curve (again, shortening the Curve).

These settings are in Properties > Object Data > Geometry:

Answer 2

You can use a Curve Deform Modifier on a mesh and animate the axis that follows the curve. By animating it from 0.0 to x, the mesh grows along the curve. Scaling to 0.0 is a bit tricky because you get a flat object. Either set all scale to 0.0 for the first frame or animate the visibility in the outliner.

Answer 3

Another way is to use the build modifier.

The thing to note with the build modifier is it builds using existing geometry, that is displaying it one face at a time, so you most likely will want to increase your mesh resolution (or use subsurf modifier) to get a smooth animation. The main difference of the build modifier is the randomize option which allows you to have a line materialise over the entire length instead of drawing from start to end. If you are using curves that means turning up the resolution in the curve properties.