When compositing, it is often necessary to match the movement of effects or other assets
to movement within your video footage.
I'm Axel Wilkinson for HitFilm.com, and in this video we will look at the tracking tools
in HitFilm 3 Pro.
I invite you to download the project files if you want to follow along.
You can track points on any video layer in a composite shot using HitFilm's Feature Tracker.
So suppose we want to add flares to the headlights of this car.
Add a tracker to the layer, and the Viewer switches to the Layer panel.
The inner red square contains the feature to be tracked.
The outer green square is the search area.
We want to position the Feature over an area of high contrast, as close as we can get to
the actual position of the effect.
In this case, we can use the actual headlight.
Then adjust the search area to ensure that the feature won't move outside the search
area from one frame to the next.
The faster your feature is moving, the larger your search area will need to be.
Click the Track Forward button to begin tracking.
HitFilm very quickly tracks through our scene, and now we have precise coordinates for that
feature on every frame of our video.
The next step is to Apply that position data, so we can use it.
In most cases, you will use a Point for this.
Create a new Point layer, then right-click and rename it Tracking.
Select our tracker again, and in the Track panel, select our new Tracking point in the
Layer menu.
Click Apply.
Nothing dramatic appears to happen, but if you now switch back to the Viewer panel, our
point is perfectly locked on to the headlight.
Now we can parent any effects we want to that Tracking point to lock them in place.
Create a new Grade layer to hold our effect, and drag a Light Flares effect onto it.
Open the Hotspot Position controls, and set Use Layer to our Tracking Point.
Zero out the position, and the flare drops right into place.
You might want to use a different flare preset, or adjust the other flare settings; I’m
going to use the Digital Blocks preset, but you can see how quickly we were able to accurately
track that scene and lock our effects in place.
When this tutorial is over, you should track and add a flare to the other headlight, on
your own.
You can also use tracking to stabilize a video layer.
Add a second tracker to our video, and Right-click and rename it Stabilize.
Let’s set up our tracker the same as the first time, but then we are going to add a
second point.
Change the Type to Double Points, and then reposition the new tracker that appears over
the other headlight.
Click the Track Back button, to track the layer again.
By comparing the position of both points, HitFilm can also detect any rotation in the
layer, and if the distance between the points changes, HitFilm will know the scale is changing.
Once the tracking is done, open the Purpose menu and select Stabilize.
This will allow us to apply the tracking info back onto our source layer and eliminate the
random camera movement.
Since we used Double Point tracking, we also have the option of applying Scale and Rotation
information.
I like the change in scale, as the car gets closer, so I’m only going to enable Rotation,
but you can turn on both if you like.
Then click Apply.
Switch back to the Viewer, and play the timeline.
All wobble is removed from the headlights, nicely smoothing the shot.
Of course, as the video is adjusted to remove the movement, we get some black visible around
the edges, which will need to be cleaned up.
This can be handled by increasing the Scale of the layer, or decreasing the size of our
Comp, or a combination of both.
If you Applied Scale from your tracking, though, then this will take an extra steps, due to
the layer Scale containing lots of keyframes.
Since I didn’t use Scale, I could just adjust the layer itself , but instead I will show
you a technique that works in all situations, so you know.
Because knowing is half the battle.
Create a new point, and let’s name this one Scale.
Then, parent our video to the point.
Now we can change the scale of the point, and our video will scale up too, imitating
its parent.
Make sure to adjust the Position as well, so that the car is roughly centered in the
frame.
Of course, now that our footage is stabilized, the effect is out of place.
But this is quite easily fixed, because now the headlight isn’t moving at all.
So in the Hotspot Position controls for the Flare, set the Use Layer to None, then just
position the effect over the headlight.
HitFilm 3 Pro also includes a special version of mocha 4, for advanced planar tracking and
camera solves.
We will discuss mocha HitFilm in another video.
Our next video will dig into the Effects panel, and teach you more about working with Effects.
You can subscribe to our channel to be notified of all our new videos as they are released.
Until next time, I’m Axel Wilkinson for HitFilm.com, and thanks for watching.