when it comes to filming a scene that's going to have some visual effects added to it there
are a couple of things that you should consider with every single shot even before you hit record
whether you're acting as the director one of the visual effects artists or even the vfx supervisor
these things are going to make it a lot easier in post-production and can save you
some valuable time here are the things that you should consider with every visual effects shot
that you set out to create the first thing is to figure out what kind of motion track you'll need
if it's a stable clip like it was shot on a tripod then you probably won't need anything at all
this is the easiest option but it can also make things a little bit
less realistic because there's no motion to ground the visual effects into the scene the
second option is a 2d track and you can do this using hitfilm's tracker both in pro and express
or the mocha planar tracker which is an add-on for express and included in pro by default a 2d point
track and hitfilm tracks the position scale and rotation and we've done a few tutorials on this
in the past the mocha tracker uses planes in your scene which are flat surfaces then there's the
three-dimensional track which you might need to do if your camera is moving throughout the scene
for this you can use mocha again or foundry's camera tracker which is included in hitfilm pro
this will create a fully 3d scene inside of hitfilm and you can place your assets anywhere in
s looking at it's looking for areas of contrast and changing pixels to determine how the camera
is moving so things that are out of focus or flat in texture will be much harder to track the next
question that i ask myself when it comes to doing a visual effect shot is will i need to rotoscope
this is something that i avoid if at all possible it can take a really long time and even then the
results won't be that great if you can throw down a green or blue screen behind your subject so
instead of masking them out you can just key them which is a much more automatic and easier process
if you absolutely have to rotoscope keep in mind how difficult it's going to be you're going to
need to break the roto into sections so don't try and mask out an entire actor using one spline
i would suggest learning how to use mocha for rotoscoping because it allows you to track the
subject as you mask which saves a lot of time you can find a tutorial on using mocha for roto in the
card on screen the next thing to consider is how would the visual effects affect my environment if
they were real so whether you plan on putting a 3d model of a car with its headlights on
into your street or creating some harry potter spell effects consider what they would do to the
environment if they were actually in your scene this involves casting light and shadows onto
your actors in location moving objects around your scene if it's a powerful effect like a shock wave
or an explosion or any sort of destruction that might happen which could be difficult to simulate
because we do a lot of light and energy visual effects here at fxhome i always take the time
to consider how the visual effects would be casting light onto the actors or environment
it is possible to fake the casting of light onto your actors or environment after you've shot
the footage but it's much more difficult and it doesn't look nearly as good as a real light in the
scene an example of a hollywood film fake casting light onto its actors would be harry potter and
the goblet of fire there are a couple of instances in this film where the actors are casting spells
but the light has been added on in post it might be difficult to tell because it goes
by so quickly but if you slow it down you can see that the light has been painted on
of course if you can't find a way to cast the light on set then the other option is to just
not have it at all the star wars prequels did this with their lightsabers here you have these glowing
tubes of energy and they're not casting any light onto the real life actors they compromise by doing
it for the cg characters but for whatever reason weren't able to do it for the live-action actors
this problem was later solved in the sequels by using props that actually lit up now that you've
considered how the vfx will affect the environment flip it around and consider how the environment
will affect the visual effects you have no idea how many times i had to say that to get it right
you should be considering the light shadows and color in your scene and think about how those
might affect the elements that you're trying to put into your scene so if your actor is backlit
and you're trying to put a 3d model standing next to them you're going to want to match the
color and lighting to put it into the scene another thing that's easy to forget is the
camera depth of field this affects whether the element is blurry or in focus and when it comes
to green screen matching the lighting between your foreground subject and your background is probably
the most important thing to keep in mind and the final tip for today is to try new techniques try
new things that you haven't done before but have a backup that you can rely on it's okay to approach
a shot and say i haven't done this before and i'm going to try something new but you should always
have a backup shot that you know you can work with just in case the new technique falls through
especially if you're doing this for a client or company being able to say this technique that
i thought was going to work didn't but it's okay because we have this one which will work as well
and that's it for this video if you have any visual effects tips we'd like to hear them in
the comments below don't forget to subscribe and we'll see you all in the next video