despite what you may believe forrest gump actually used an incredible amount of vfx
for a movie of that time from the very beginning with this feather sequence which we'll explain
later and continuing right throughout the movie but aside from the obvious uses of the effects
like getting tom hanks to appear in a variety of historical footage like this shot with lyndon
johnson this shot with john lennon or this one with richard nixon visual effects were
cleverly used for these four different and very necessary reasons one for augmentation
sometimes a set or location where a shot is filmed isn't exactly how the director first envisaged a
road is shorter than needed a stadium is smaller a public area is less populated or in some cases
the budget just won't allow for anything better so in this case the vfx teams will adjust extend
and augment the environment to the director's specifications in this scene forrest had to
speak to a massive crowd in the lincoln memorial unfortunately to create a crowd this big you'd
need around a quarter of a million people so the team shot tom going up to say his
speech on a motion control camera in front of a large crowd at the front of the stage
after completing that shot they then moved the crowd to different quarters all around
the reflecting pool and filmed it with the motion control camera following it with the exact same
moves it had previously these shots were then composited with the original plate of tom
a similar thing was done for the scene where forrest plays football for the
university of alabama this was actually shot on a football field in the university of east la
but here instead of repositioning and filming the same crowd they used digital map paintings
to extend both the stadium and the crowd this was also done for the ping pong game in china
which was actually shot at paramount studios and yes that ping pong ball is actually cgi
2. vfx were used for impact it's not uncommon for a shot to lack the visual punch or emotion the
director is looking for a battle scene may seem empty a fight scene too slow or an explosion to
feeble so the vfx team will then use a number of different techniques to give the shot the impact
that is required in forrest gump the director robert zemeckis wanted the first vietnam sequence
to be loud and busy with a lot of helicopters flying past in the background but this just
wasn't economically or logistically possible and they could only manage to get two to fly through
so to solve this problem at the same time as they were shooting the scene with the
two helicopters flying past in the background they had other camera operators hidden behind
props and set pieces taking telephoto shots of them as they went by all of these images
were then composited into the shots and animated to look like they're flying through
3. vfx were used for safety although most shots in movies are relatively
safe to shoot some of the dangerous shots that we see in them can still be quite dangerous to
film as actors aren't always trained to do some of the stunts required in a movie
stunt people or stunt doubles are used for anything deemed too dangerous for the actor
unless your name is tom cruise or jackie chan of course but sometimes stunts are too complicated or
too dangerous even for a trained professional and here is where the vfx teams will step in
for the shot when forrest is being chased by some guys in a truck the director wanted the
truck to be right close up to tom but if tom had tripped up the truck would have driven over him
so to avoid this danger they filmed a plate of tom running on his own with the camera locked off
they then filmed another plate of the truck on its own and panned it when it turned
then they did rotomats of tom and composited both plates and this guy here is a stuntman
they did the same for this shot when forrest enters the football field
number four vfx were used to solve problems we'll just fix it in post is a phrase that
filmmakers love and vfx vendors hate but sometimes there is just no other way around it
this is when vfx teams have to get their thinking caps on and oddly enough it's also when they're
at their most creative the ambush sequence in this movie brought its own set of challenges
like how do you blow up two soldiers without actually hurting anyone the solution they came
up with was to shoot one plate with the cameras locked off and the actors attached to wires and
getting pulled out of the shot then they shot two crew dummies laid on top of an explosive
and wired so they too could be pulled out of the shot and in doing so would come slightly apart
they also shot some different pyro elements and explosions at different frame rates
then using high-speed compositing software from discrete logic called inferno they combined the
fireball with the dummies and then cut from the live-action plate to that composite right here
another problem that appeared in this sequence was when tom hanks had to carry a 90 kilogram michael
t williamson out of the jungle whilst napalm exploded behind them once again with the camera
locked off they filmed a stuntman carrying another stuntman from a distance and then stumbling then
just when he stumbles right here they morphed into a shot of tom carrying williamson who was
obviously too heavy for tom to carry and so was attached to a wire hanging from a crane to pick
up his weight for the napalm component of the shot the special effects team set up a tremendous
amount of pyro elements and gasoline to mimic napalm all running up towards the cameras which
were set at various different speeds they then composited the actors in front of the pyro footage
morphing from the stuntmen to the actors right on the stumbling point
something you may not have noticed in this shot is that these jets and the napalm
containers they drop were cgi and these birds flying from the cornfield were also 100 cgi
another problem they had to solve was the feather sequence how do you control a feather that's being
blown about randomly in the wind you could use a man in a green suit to puppeteer the feather
but mr green here can't fly and so the feather sequence was done by first filming the entire
shot without the feather filming a feather on a wire in front of a blue
screen and then superimposing and animating its position on top of the footage however
aside from it needing to make reflections on this car or on this wet floor here the feather
still needed to transition from superimposed to real and this is where vfx came in handy on the
original plate they lent a real feather against tom's shoe which was then digitally painted out
then by using a cg feather they were able to make the transition from blue screen feather
to cg feather and then finally animate it to fall and be crossfaded into the real feather