Star Wars is back and we’re all going to get super excited like it’s 1999. Both trailers
have set the internet alight, so let’s hope that JJ’s got a plan. The Force Awakens
isn’t out until December but that’s not going to stop us making a lightsword tutorial
RIGHT NOW. We don’t know any Jedi but we do know some
Kendo experts, so we headed out and shot some new material. Is it just me, or does Kendo
gear look kind of like Kylo Ren’s outfit from the new movie?
Here’s how lightsword effects work: first, you film your actors with real props. You
shoot with a real prop blade for two reasons: 1. So that the actors have something to react
against, as it’s impossible to fight properly without that physical impact. And 2. to provide
an animation reference for the visual effect. There are some exceptions - if you need to
show the lightsword turning on or off, it’s usually best to shoot with a bladeless prop,
so that your actor is just holding the hilt. That way you can create the ignition VFX without
having to paint out the prop blade. Similarly, if you need to show the blade impacting something,
it can be a lot easier without a blade, or with a short stunt blade.
The second step is rotoscoping. The lightsword effect is almost always rotoscoped. Rotoscoping
is a technique whereby individual frames of video or film are drawn over by the VFX artist.
That’s how it was done in 1977 and that’s still the main approach in 2015, although
it’ll be interesting to see if the ep7 team has come up with new techniques. The reason
it’s such a manual process is that the blade tends to move so fast in a fight that it receives
a huge level of motion blur, often disappearing entirely for multiple frames. It’s impractical
for a computer to automatically track that movement.
Back in the day this meant pain. So much pain. So with The Force Awakens on the way, we set
out to make HitFilm 3 Pro the best, fastest and easiest way to make lightswords.
Download the project files if you want to follow along.
I’ve got the ‘Tutorial’ composite shot open with the footage ready to go. In the
Effects panel I’ll locate the Lightsword ‘2-point auto’ effect. Although you can
drag it directly onto the video layer, it actually makes more sense to give it its own
layer. That gives you more control, making it easy to manipulate the effect without affecting
the video clip. To do this, in the New Layer menu on the timeline
create a new plane, with the same dimensions as the video. You can then add the lightsword
effect to that plane. So we currently have a black frame with a
blue lightsword in the middle. We got some work ahead of us.
First up, let’s sort out our blending. By default the effect is using a screen blend.
This makes sense if you do apply it directly to a video layer, as you’ll see the video
underneath. But we’ve applied it to a black plane layer, so all we see underneath is…a
black plane layer. Instead, let’s open up the lightsword in
the Controls panel, and find the Blend property, right at the bottom of the lightsword’s
options. I’m gonna switch this to None. What this means is that the only thing that
is rendered from this layer is the effect itself - the black plane is no longer rendered.
I can now go to the PLANE’S blend options, up in Layer Properties, and switch the entire
layer to Screen blend. We now have a nice lightsword shape floating
on top of our video. With the effect selected in the Controls panel
or the timeline, you can see the two control points in the Viewer. These can be moved around
to match the effect to your prop. Before we do anything, it’s time to turn
on some keyframing. The ones you will basically always want to activate are found in the hilt
and tip groups. Turn on keyframing for both Position properties. PROTIP: don’t rotoscope
an entire shot, only then to discover that you didn’t turn on keyframing. Not that
I’ve ever done that. I’m talking entirely hypothetically. Only an idiot would do that.
So, I’ve positioned those points. Now let’s move forward a couple of frames and update
the points positions. Sometimes the lightsword effect itself actually makes it kinda tricky
to position the points accurately, because it obscures the source footage.
The good news is that disabling the effect using the checkbox on the timeline doesn’t
turn off the control points. So you do have the option of turning off the effect while
rotoscoping, if that makes it easier. Rotoscoping is a slow process which requires
patience. I tend to roto every other frame, which immediately halves the amount of work.
You can then go back and add additional frames in-between if necessary. The general rule
of thumb is that the faster and more erratic the movement, the more keyframes you’ll
need. The benefit of HitFilm’s system is that
it keeps everything to a minimum, with you only needing to position two points. You’ll
note that the hilt and tip do also have inputs for other layers, so you can drive the position
from other animation or tracked data if you so wish.
With the effect turned on we can see what’s going on. And what is pretty obvious is that
we need to do some customisation. Think of yourself as a Jedi, constructing your first
lightsword and picking your crystals. There are three main elements to the lightsword
effect. The core, the inner glow and the outer glow.
The core is the main shape, which should entirely cover your prop blade. This is all pretty
self explanatory - you can adjust the width, soften the edge with the feather property,
and alter its colour. The stability option is interesting - it adds an automated wiggle
motion to the shape, randomising the width on each frame. At 100 stability the shape
won’t change at all. The lower you set the stability, the more the shape will change.
This gives the blade an energetic appearance, just like the hand-drawn sabers from the original
trilogy. Note that if you’re using the screen blend,
any core colour other than white is likely to reveal the layers underneath. So keep the
core either white or very near-white. Note that you can further adjust the shape
in the hilt and position groups, tapering the blade at either end. This can be particularly
useful if you have a lot of perspective on the blade.
As for the glows, it’s really a matter of taste, but I tend to like having a small,
intense glow right close to the core, and then a much softer, large, more diffuse glow
around the outside. Note that you can adjust the width and the alpha of both glows. The
alpha is used to change the visibility of the glow.
Note that the inner glow also has stability and flicker options. The stability option
is much the same as the core’s stability, in that reducing stability causes the width
of the glow to shift randomly. The Flicker setting is similar but affects the inner glow’s
brightness, rather than its size. Used in combination these give the lightsword a dangerous,
intense behaviour. You’ll notice a Distortion setting down
at the bottom of the controls. This adds some edge distortion around the shape. With zero
distortion the effect can often look overly computer-generated, because it’s a bit too
perfect. A little bit of distortion gives it a more authentic, 1980s-style hand-drawn
roto look. The great thing about all these flicker, stability
and distortion adjustments is that they’re built right into the effect, which means you
don’t need to manually create them using keyframing.
As you continue rotoing the clip, you’ll note that as the real blade moves faster it
fans out and becomes increasingly blurred. lightswords in the Star Wars films are weird
in that they don’t receive a natural motion blur. Instead, they get a solid trail of light,
which doesn’t fade away. In the old days you had to manually adjust the width at the
tip and the hilt to get the correct trail, but HitFilm 3 Pro handles all that for you.
As I position the points on these fast-moving frames, note how the lightsword shape is fanning
out automatically to accommodate the motion blur. HitFilm is aware of the relative motion
of these points, and also understands the inherent behaviour of a physical blade. This
is used to work out a realistic motion path, which is used to draw the lightsword.
Using the default setup, you generally want to position your points on the leading edge
of the blade. Keep an eye on where the blade is moving, and keep the point on that edge.
Remember that it’s entirely possible for the tip and the hilt to be moving in opposite
directions. Right, I’m going to roto the rest of this
clip, then we can dig into some of the more advanced properties. FAST FORWARD TIME!
OK, let’s talk about path interpolation. Sounds exciting, no?
If you look at the tip and the hilt, you’ll see that they’re not drawn as straight lines,
but as undulating curves, depending on the movement of the blade. This is the path interpolation
at work. If you reduce the Scale property, that curvature
lessens, until it reverts back to straight lines. For natural lightsword movement you
generally want to leave the Scale on full. The actual curve shape is worked out automatically,
but you can influence its overall shape using the hilt and tip rotation wheels. Most of
the time you can leave all this on the defaults, but if you need to go in and fine tune, you
can. Moving on, let’s talk about Motion Persistence,
which determines the maximum amount of motion blur applied to the shape. This is what determines
how much of a trail is left behind as the blade moves around. You’ll need to adjust
this to match the amount of motion blur present in your footage, which will depend on your
camera’s settings. The auto scale settings determine when the
motion persistence actually kicks in. If you turn off auto scale, then the length of the
trail is set solely by the motion persistence setting. This means you can, if you want,
have a crazy long trail that stays on screen forever. Not right for lightswords, but might
be interesting for some other effect you’re after.
With auto scale ON, you get a bit more control. The speed and swing thresholds restrict when
the motion persistence trail activates. If the speed and swing aren’t fast enough,
the trail isn’t drawn. This means you can ensure you don’t have a smeary blade that
is always shifting shape, and make sure that it only gets that motion trail when it needs
it. On top of that there’s the minimum persistence.
This can be used to maintain a minimum level of trail even if the speed and swing thresholds
haven’t been met. Handy if you have footage that is inherently quite blurry.
So, that probably all sounded pretty confusing. The good news is that for general lightsword
action, all you really need to worry about is the motion persistence setting. Find a
frame with fast movement, and adjust that setting so that the trail covers the blur.
And you’re done. But it’s always good to know that finer control is available, should
you need it. There’s one other setting I skimmed over,
which is the persistence shift. This adjusts where the trail is drawn, relative to the
control points. So like I mentioned earlier, with the default settings you should set your
control points on the leading edge of the blade. If for some reason you’d rather have
your control points in the middle of the blade, or the trailing edge, you can use the persistence
shift to move the trail back and forward in time relative to the points.
All of that customisation aside, the core of this effect is the ability to quickly keyframe
a couple of points and generate an authentically drawn lightsaber, minimising the effort of
all that rotoscoping. There’s a few other things going on in the
lightsaber sequence which I’m not going to go intil full detail on because they’re
covered elsewhere, but if you dig into the tutorial sequence that’s included you’ll
see what I’ve actually done. But one thing to note is that as long as you
put your lightsaber effect on a plane layer like we did when following this tutorial,
you can just mask that layer and the masking will do exactly what you want it to do. So
you maks out the shape of the lightsword but you still get that glow coming around the
edge of the mask. This is really key because what you don’t want to do is end up masking
the glow itself, because that looks really bizarre. You need the spill of that light
coming around the edge of whatever you’ve masked.
And you’ll also see that whenever the lightsaber collide you get this kind of intense clashing.
This is actually just a completely standard HitFilm light flare where I’ve just keyframed
its intensity to suddenly appear when the lightswords collide and then over a couple
of frames have it diminish away again. I’ve then enhanced that collision by adding on
some additional effects, such as the anamorphic light flares which just gives it a bit more
of a kind flaring out. The last bit you may have noticed is that
halfway through the clip one of them ends up with the lightsword connecting with his
head, generating a load of sparks. Now that’s probably not what would happen if you hit
someone with a lightsword, but we’ll gloss over that. That’s actually an incredibly
simple effect, I didn’t need to go into the particle simulator for that - you obviously
could, if you wanted a bit more interaction - but that is in fact just a very simple bit
of stock footage which I’ve composited on top there.
Any decent sparks stock footage will work for that, it just required positioning it,
shrinking it down into position and just timing it up so that it appears when that blade connected.
And that’s about all there is to this lightsaber sequence. The whole point is that it’s as
quick as possible and as easy possible, so that you can get out there and start making
your lightsaber fanfilms without knowing that you have hours and hours and hours of roto
work ahead of you. So there’s a few months left until the Force
Awakens, so you’d better start planning those fanfilms right now, and we really look
forward to seeing what you come up with. As always, many thanks for watching and I’ve
a pretty good feeling that we’ll be back later in the year with more Star Wars-related
tutorials.