This tutorial from Axel Wilkinson accompanies our Kylo Ren lightsaber video and takes a
look at how mocha HitFilm was used to quickly and easily roto the lightsaber handle for
masking in HitFilm.
Hello, and welcome to another HitFilm tutorial.
We recently looked at how to replicate Kylo Ren’s lightsaber in this tutorial, and part
of the process involved using a rotoscoped mask, which I created in mocha HitFilm.
Since this is a technique that can be directly applied in a huge variety of projects, and
which isn’t strictly part of the lightsword creation process, I wanted to separate it
out into its own tutorial.
I’m Axel Wilkinson, for Hitfilm.com, and we are going to look at how you can quickly
rotoscope moving objects in HitFilm 4 Pro, using mocha HitFilm.
If you want to follow along, please download the accompanying project file.
So, in the Finished Shot comp, we have a bunch of points, for positioning the effects, we
have our footage, and then we have three particle layers creating the main blades of the lightsword.
These overlap onto the prop hilt, so we want to create a mask that cuts them off at the
edges of the prop, so they look like they are coming from inside.
This existing Hilt Mask layer is simply a duplicate of our footage, which uses a mask
so only the hilt is visible.
It sits above our blades, effectively hiding the area where they overlap onto the prop.
Let’s delete this layer, and we will rebuild it from scratch.
To send our video clip to mocha, right-click the clip on the timeline, and choose Open
With Mocha HitFilm.
Now, since I have already done this once, and I have a project that uses this name,
I get this message asking if I want to overwrite the project.
I’ll click yes, but you won’t get this message if you are opening the clip in mocha
for the first time.
Once the clip opens in mocha, the In and Out points will be set to the same in and out
points that are used on the HitFilm timeline.
In this particular shot the entire clip is on the timeline, but this is an important
difference between opening mocha from the HitFilm media panel, vs. opening a clip into
mocha from the HitFilm timeline.
If we jump back to Hitfilm, you are probably familiar with the option to create a new Solve
using Mocha HitFilm in the media panel.
When you use this option, you can manually set the in and out points, if you don’t
want the entire source clip to be used in mocha.
If you send the clip from the timeline to mocha, though, as we did, then the entire
source clip still opens in mocha, but the In and Out points will already be set for
you, based on the portion of the source clip that is used on the timeline.
Now, the portion of this shot that needs masked is at the end, and only lasts as long as the
blade effects will be visible.
So, we will start our track from the end, and work backward.
Select the X-Spline tool, and we will draw a spline around the hilt of the lightsaber.
This spline can be clumsy and random, all it is doing is tracking the movement of the
hilt.
We will create the actual mask later.
When you have drawn all the points you need, just right-click to close the shape.
So, with a rough shape drawn, we make sure the Minimum percent pixels used is nice and
high, at 90, and click the button to start tracking backward.
The hilt is going to disappear from view, so naturally the track will get lost, at which
point we can stop.
The point where it is lost is actually before the blades appear, though, so we have all
the tracking we need on this layer.
Rename this layer to Hilt Track, and now we will create the mask.
Move back to the last frame, select the X-Spline tool again, and this time, carefully draw
a mask around the shape of the hilt.
If you want to zoom in, hold Z and drag the mouse upwards.
On this top quillon, where you can see into the emitter, make sure you keep the mask on
the closer edge, so only the front of the hilt is masked.
Adjust the points as needed, so you have a nice tight spline around the hilt.
Now, this next step is the key to rotoscoping in mocha.
Rather than track this spline, we are going to use the tracking info from the spline we
created earlier.
In the Layer Properties, open Link to Track, and select our Hilt Track.
Let’s rename our current layer to Mask, to keep things clear.
To review, we are using two layers, one rough track to handle the general movement, and
a second layer, linked to that tracking, to create the more precise mask we need.
There are still going to be occasional wanderings in the mask that need correcting.
But by linking our mask to a rough track, it greatly reduces the number of keyframes
that we need to create.
So, work through the footage, adjusting the position of the mask, or its shape, as necessary
to re-align it with the prop.
If you want to move the entire mask, just drag to select all the points, then move any
one of the points to reposition it.
Individual points can just be dragged to reposition them.
Keep this up until you are happy with the mask’s position.
Here I have a nicely tracked mask spanning 70 frames, using only 3 keyframes.
Not too shabby.
Of course, if you are masking a more complex subject like a person, then more keyframes
will likely be necessary, but you can still save a load of work by using mocha for your
roto.
Once we have the mask done, we need to export it, so we can use it in HitFilm.
This doesn’t require a camera solve or anything, it is done right in the Track Parameters,
by clicking Export Shape Data.
Make sure you have the Mask layer selected, then click the Export Shape Data button.
Click Save, then give your new composite shot a name.
I’m going to use Hilt Roto Mask.
Once that is saved, switch back to Hitfilm, and we can use the Import Composite Shot command
to select our new comp, and click Open to import it.
It opens in a new timeline, and we just want to copy the entire video layer, with its mask,
then move to Finished Shot comp, which contains our effects, and paste it in.
Reposition the layer on the timeline so it starts at frame 0, and sits right above our
blade effects, and it automatically lines right up.
The last thing to do is feather the edges a bit, so a tiny bit of the glow from the
blades still affects the edges of the prop.
Open the Mask controls, and adjust the feature to suit your taste.
I used a feather of 3.
And there you go.
You now know the basics of creating a rotoscoped mask in mocha Hitfilm.
If you haven’t seen it yet, check out the accompanying tutorial, where we discuss how
to create the other effects in the shot we used this mask for.
Tune in next week for something awesome from Josh and Kirstie.
At the time of filming this, I don’t know what it’s going to be.
But I do know it’ll be awesome.
Subscribe!