Here's one way, and I'm sure there are others.
Open the layer window for a Solid, and choose the paint brush.
Pick a color, and a small, 3 or 4 pixel brush.
Set the Spacing to something like 200.
Click once to make a dot. Then decide where you want the dotted line to end and Shift-click there.
Now when you twirl down the transform properties for that paint stroke, you can rotate the beam, making it "point" where you want it to.
In the video it looked like maybe certain areas were motion tracked, maybe not.
But I'm sure someone has a clever expression, or knows some other way, to somehow tie the rotation of the stroke to the position of a track point.
Hope that helps.
One way to do this would to be to make a solid with an adjustment layer in between it and the layer you want it affect and find the Audio Waveform under generate, this makes an editable dotted line, you can then change the opacity color and other things and rotate it as you like, this may not be quite what you were looking for though. Who knows? maybe it will look better?
Hey James, I think I figured out how to achieve the effect used in the Lie To Me intro. I've been wondering myself how to do this, and after some playing around, I figured it out. Here's what to do:
I created a new solid and applied the Beam effect to that layer. Next, I created another new solid and applied the Grid effect (Generate > Grid). I then adjusted the settings on the Grid effect to the following (these may differ depending on your Composition Size): Size From - Width & Height Sliders; Width - 10; Height - 200; Border - 5. I then adjusted the Scale of the solid layer with the Grid effect applied, so that the height only is at 560% and then positioned so that no horizontal lines show on the stage. Then, making sure the Grid layer is above the Beam layer, add a Luma Matte to the Beam layer and it should create a dotted line. This works great unless the Beam is vertical. If you are primarily using the Beam in a Vertical position, then you would need to invert the Grid settings so that only Horizontal lines appear.
Does that make sense? Let me know if it doesn't work or make sense.