I'm assuming you mean this:
You'll need to learn about Motion tracking, the Beam Effect and basic expressions made with the pickwhip.
- Open the footage you are going to use in the Footage Panel by double clicking it in the Project Panel
- Trim the footage to the portion you are going to use in the final shot by setting an in and out point using the CTI and Alt/Option + [ and Alt/Option + ]
- Select the trimmed footage in the Project Panel and choose File>New Comp from Selected
- Add a null to the timeline
- Open the Motion Tracking Workspace
- Select your video in the timeline
- Move the CTI to the frame where you want to start seeing the pointy gray thingie
- Select the video layer as the Motion Source in the Tracking Panel and choose Track Motion (This should open the Layer Panel - if it does not open it manually by double clicking the footage in the timeline)
- Move the Tracking area box (It's not point but detail tracking) to the car and adjust the size and search area enough of the car to get a good track (the default is way too small most of the time)
- Run the track for the length of time that you want to have the grey thingie point at the car
- Check the track to make sure it's good and make any corrections you need to make
- Select the Null as the Target in the Tracking Panel and press Apply
- Back in the timeline and the comp panel press the U key to reveal the Tracker 1 keyframes in the footage
- Move the CTI to the start of the timeline then press the k key to jump to the first Tracker 1 keyframe
- Add a new solid the size of the comp to the timeline and trim the In Point by pressing Alt/Option + [
- Apply Effects>Generate>Beam
- Set the Length to 100% and the Time to 50%
- Set the Start, End, Colors and Softness to get the look you want
- Add a graphic for the title block to the top and put the Anchor Point in the center of the graphic then trim the in point of the graphic
- Reveal the position property of the graphic by pressing the letter p
- Add an expression to the Starting Point of the Beam by dragging the pickwhip to the position property of the Graphic
- Add an expression to the Ending Point of the Beam by first typing "p = " then drag the pickwhip to the position property of the Null
- You can then split the array and subtract some pixels from the Y value to move the ending point up
- Trim the end points of the graphic and the beam layers by moving the CTI to the end of the pointer effect and press Alt/Option + ]
You'll get something that looks like this:
The expression for the Beam End Position modified to raise the end point above the Null looks like this:
p = thisComp.layer("Null 1 Target").transform.position;
x = p;
y = p -60;
There are lots of ways to do this effect but I think this is the easiest.
Thank you very much for this detailed explanation.
I figured out how to do this in a very similar way with expressions and everything.
I appreciate you taking the time to write this out and screenshot everything. Hopefully this helps someone in the future as well.
Can you make a video on how to do this because it's confusing for me in text form.