Today we’re talking about how to fly. Or,
more specifically, how to take off. Using a super suit. Made of metal. Iron metal.
Our Heads Up sketch was put together because we wanted to do a cool heads-up display effect
using HitFilm 4 Express. But we also couldn’t resist throwing in a few shots made in HitFilm
4 Pro – such as the take-off. The repulsor boot jets and smoke was made using HitFilm
4 Pro’s particle simulator, as well as some very mundane filmmaking trickery.
Here’s how we did it. Here’s what we started with. If you check
out the behind the scenes, you’ll see that we achieved this by raising Kirstie’s legs
up with a pole while she sat on a table. This made it easier for her to lift those heavy
boots feet vertically. Obviously, if you’re putting a pole underneath
an actor’s legs and spinning them over the back of a table, you want to make sure there’s
something nice and soft on the other side, just in case they fall off..
Because that’s totally what we did. Kirstie was completely safe the entire time.
… [shifty eyes] We shot a separate plate with a practical
light, which was comped in to remove the unrealistic shadows on the floor.
The boot movement was tracked, and then two separate particle systems were added: one
for the repulsor jets and one for some smoke. A nice, big, juicy flare was slapped on top
of the whole thing, and we even did some re-lighting using mocha to make it look like the boots
were being illuminated by the jets. Mix it all together and you end up with something
like this. Time to get our VFX on.
In this tutorial I’m going to be focusing primarily on the particle effects. If you
want more details on any of the other techniques let us know in the comments! We’ve got project
files to download so you can follow along, so hit the link in the infocard or video description.
Tracking the boots is a good job for mocha, which is included with HitFilm 4 Pro. I’m
going to add my video clip to the editor timeline and choose ‘Open with mocha HitFilm’.
This’ll send it over to mocha. Mocha uses planar tracking, which is able
to sample a large area and is great for tricky shots where there’s a lot of blurry movement
and a lack of sharply defined detail, as with these boots. Axel’s got a whole series on
using mocha, so do check those out. I want to track two areas for this boot, so
that I can add a jet to the front and back. I’ll draw a large, roughly oval shape around
this front section, and another somewhere back here on the heel. I can then track through
the shot to gather the data. Mocha will track both areas at the same time. You don’t need
to worry much about the specific shapes you’re tracking, and if you see the shapes skewing
a little that also doesn’t actually matter in this case.
To get this back into HitFilm, I’ll selected the first track, then go to the Export Tracking
Data option and set the Format to ‘HitFilm Transform Data’. Saving this creates a new
composite shot, which I can bring into HitFilm. I’ll do the same for the second track.
Back in HitFilm, I’ll choose ‘Import Composite Shot’ and bring it both those composite
shots. First the Front jet, and then the Rear jet. They get imported as new composite shots,
with all the relevant media. Check out this point layer for the rear jet – see how it’s
tracked on perfectly, and even has the correct rotation as the boot moves around? That’s
the power and ease of mocha right there. I’m going to copy this point layer, then
switch over to the other composite shot containing my front jet track, and I’ll paste in the
rear one. This means we now have both tracks in the same timeline.
I’m going to click the gear icon down here and rename this to ‘Main comp’, so that
I know this is my main working timeline. I’ll actually delete the imported Rearjet stuff
from the media panel because I don’t need it anymore.
We now have our video with two rock solid, tracked point layers. I’m just going to
rename some of these layers to make sure everything’s nice and clear. We’re now ready to start
adding some effects. In the project zip you downloaded you’ll
find a preset file called Jets. To add this to your effects library, right click anywhere
in the Effects panel and choose Import Presets. You can select that Jets preset to bring it
in. I’ll now search for ‘Jets’, and drag
it down onto the timeline. This creates a new particle simulator layer. The first thing
we want to do is attached our particle emitters to the boots. Inside the particle sim, open
up the Emitters group, then the ‘Left boot front’ emitter and find its Shape group.
In here you can attach the emitter to the Front jet layer. The same can be done for
the rear one. I’ll also make sure the position properties
are zeroed out, so that they’re not offset at all. Finally, our circular emitters are
a bit large for the framing of this shot, so I’ll drop their scale down
And now, scrubbing through, we have out jet thrusters attached to the boots. Spiffy!
The next thing to do is set up our floor, so that the jets aren’t just disappearing
down and out of shot. Having this as a static shot without any camera
movement makes this pretty easy, as we can simply estimate the scene by eye. I’m going
to create a new Plane and use this as the floor, so that I can re-use it for any other
particle layers we make. I’ll switch this Plane into 3D, then flip
it on the X axis by 90 degrees so that it’s flat.
Next up we need some kind of reference for our scene. Conveniently, the boots start off
flat on the floor, so we can assume that on this frame the tracked points are more-or-less
at the floor position. On a
frame where the boots are on the floor, I’ll
now move my 3D floor plane down in the shot until it’s connecting with and deflecting
the particles. We can assume that is the correct position for our floor.
This isn’t an especially scientific way of doing things, but for a static shot like
this is works just fine. OK, let’s customise the look a bit because
everything is a bit big and over-bright right now.
The quick way to do this is to simply go up to the particle simulator’s layer’s main
transform group and drop the scale down. About 65% works for me.
I’m also going to scoot the entire particle layer to the right, so that it only kicks
in when the boots start lifting off the ground. If I put my playhead where the boots start
lifting, I can then shift the particle layer to get my timing right.
Time for more fine tuning. I’m going to focus on the front jet first. The main issue
I have is that the sparks are lasting too long, and flicking off in weird directions.
So I’ll go into the Left boot front emitter, go into particle systems, find the Sparks
Movement group and drop their Lifetime down to 0.5.
I’m now going to select the Plasma particle system, then switch to the Lifetime panel.
There’s already an alpha gradient going on, but I’m going to add an additional tab
at the end so that it fades out completely, and then I’ll select this second tab and
click somewhere in the middle to copy it. By adjusting this I can keep the plasma jets
nice and visible while they’re in the air, but have them disappear quickly once they’re
hitting the ground. Do check out Axel’s tutorials on the particle
simulator if any of this is making your brain hurt.
With particle effects you could tweak it forever, but I’m going to park it here. Rather than
tweak the rear jet to match, I’m actually just going to select the Left boot rear emitter,
delete it, and then copy and rename the front one. I’ll need to set its Emitter back to
using the rear track, of course. I’m pretty happy with the general particle
behaviour. Next up, I’m going to add additional effects to enhance the look. So currently
we have the jets this orangey color, but it’s not as intense as I’d like. So I’m actually
going to grab the Hue, Saturation and Lightness effect and use that to drop the Saturation
all the way down to zero, leaving us with a monochrome result.
Next up, I’ll grab our trusty color vibrance effect and add that after the HLS. This creates
a much punchier orange glow. The cool thing about color vibrance is that it retains all
that intensity while adding the hot colorisation. It’s also super easy to tweak the colors
– if I want blue jets, it’s not a problem. Lastly I’ll add Heat distortion, because
heat distortion makes everything better. I’m going to increase the scale and the distortion
settings, creating an undulating kind of look, and I’ll put diffusion strength all the
way up to give it this localised blurring. You can see how the heat distortion gives
the jets an unpredictable, more gaseous appearance. These jets are pretty bright, so I’m going
to add a new Plane layer above everything else and then add the Light flare effect.
In here I’ll switch to the Sun Glare effect and set the hotspot position to one of the
boot tracks. It’s then a matter of fine tuning the effect to get the exact look I
want – which is a nice, diffuse glow on top of the particles.
I’ll use the color vibrance effect again to give it some oomph, and apply a blur to
soften out the flare in general. Light flares and particle simulations share
a common factor, which is that they often come down to experimentation. It’s not always
possible for me to explain the exact process by which I arrived at the finished effect,
because it’s a more organic thing. Tweaking this, adjusting that. It’s about familiarising
yourself with the available options and understanding how they interact with one another.
OK, I’ll duplicate that flare and attach it to the other jet.
Now it’s time to create some smoke. For this I’m going to create it from scratch,
rather than using a preset. So, add a new particle simulator, sandwiched
between the flares and the jets. And we’re going to do something like this…
In the Emitter shape, I’ll change it to Circle, and attach it to the Front jet. I’ll
change the trajectory to Cone and point it straight down by setting the Y rotation to
-90, and go for a pretty wide cone radius. I’ll add a default Force for gravity, and
set up my deflector to use the same floor plane as earlier. That’s why it’s useful
to have an actual plane as your floor, as it makes it easy to re-use it.
In the particle system’s appearance I’ll switch to a built-in texture and select Smoke
Thickness 3. To stop the textures from all looking the same, in Appearance variation
I’ll change the texture angle to 1 – which means each texture can be at any angle – and
the angle per second to 30, so that they’re all rotating a bit.
I’ll boost the speed up to 2000 in movement, drop the bounce to 0 and the friction down
to 10. In Movement Variation I’ll add some variety to Life, of 0.5s, Scale of 30% and
Speed of 100. With something like smoke you don’t want it to all behave identically.
In the lifetime panel I’ll go to Alpha, switch to Gradient and add some tabs so that
each particle fades in and out over its lifetime. In Scale, I’ll add a handle at the end and
increase it to 200%, so that the smoke gets bigger as it fades out.
Lastly, I’ll add our good friend heat distortion. Scale I’ll set to about 90 and distortion
to 200. Heat distortion REALLY helps with smoke effects, adding an organic, chaotic
element which is hard to build into actual particle behavior.
And that should give you something a bit like this. All that remains is to duplicate the
emitter and assign it over to the other tracked point.
As with any VFX shot, it’s the fine details that bring it all together, so this is when
we layered on additional details, like hiding the floor shadows and masking the and re-lighting
the boots. Whether you need to go to those lengths will depend on the needs of the shot,
how long you’re lingering on it and all sorts of other factors.
Every single setting I’ve just shown you is entirely up for grabs – this is what I
came up with, but I’ll bet you guys can do better. Give it a whirl and see what kind
of jet and smoke effects you can come up with. The particle simulator in HitFilm 4 Pro really
is infinitely customisable, so don’t be afraid to get your hands dirty.
Keep massaging the shot until it looks right – in this case I think we could definitely
do with far more smoke particles. As always, use what you need to get the shot.
Don’t kill yourself trying to make a scientific simulation.
We had a ton of fun making Heads Up. What would you like to see us do next? Let us know
in the comments – and hit that subscribe button if you haven’t already.