Animation
works
like
this,
suppose
you're
making
a
Western
and
you've
been
trying
to
shoot
a
saloon
sequence
of
a
glass
of
beer
sliding
quickly
across
a
bar-top
and
into
the
hand
of
the
actor
playing
the
sheriff,
but
after
879
tries
he
cannot
seem
to
catch
it
and
the
glass
goes
crashing
onto
the
floor
every
time
and
you're
down
to
your
last
glass.
Animation
could
solve
this
problem.
Measuring
the
entire
travel,
the
glass
travels
12
feet
down
the
length
of
the
bar.
If
this
distance
was
traveled
in
2
seconds
of
actual
time
(before
it
hit
the
floor)
this
is
the
real-time
speed.
Since
film
runs
at
24
FPS
real-time,
you
have
48
frames
to
move
the
glass
from
point
A
to
point
B
(the
sheriff's
hand).
Since
the
distance
between
points
A
and
B
is
12
feet,
you
do
a
little
math
and
discover
you
have
to
advance
the
glass
3
inches
for
every
frame
you
shoot
to
get
the
glass
to
slide
at
a
constant
rate
of
speed
to
the
target.
The
breakdown
looks
like
this:
12
feet
divided
by
48
frames
=
3
inches
per
frame.
Simple
stuff.
Set
the
glass
on
the
bar
at
its
starting
position.
Lock
the
camera
down
(pointing
at
the
bar)
and
don't
move
it
anymore.
Shoot
only
one,
single
frame
-
then
advance
the
glass
3
inches
toward
the
sheriff's
hand
(tell
the
sheriff
not
to
move
until
the
glass
hits
his
hand).
Shoot
another,
single
frame.
Advance
the
glass
another
3
inches.
After
advancing
the
glass
48
individual
increments
of
movement
in
48
frames,
the
results
on
film
will
be
very
similar
to
the
"live"
shots
(except
the
sheriff
actually
catches
the
glass
in
the
animation).
There
will
be
some
differences.
First,
the
"live"
frames
will
show
a
little
motion
blur
on
the
trailing
edges
of
the
glass
because
it
had
real
velocity
at
the
time
of
photography.
The
animated
frames
of
the
glass
will
not
have
this
blur
and
appear
very
sharp
because
its
velocity
at
the
time
it
as
photographed
was
actually
zero.
That's
what
gives
animation
its
surreal
quality.
Second,
when
a
glass
of
beer
is
slid
down
a
bar,
friction
makes
it
decelerate.
Therefore,
some
math
skills
are
required
to
calculate
the
varying
positions
of
the
glass
as
it
slows
down
-
yet
reach
the
sheriff's
hand
by
the
48th
frame
photographed.
This
means
that
the
increments
of
movement
do
not
necessarily
have
to
be
equilaterally
proportioned.
In
fact,
by
manipulating
the
proportionate
advance
of
the
increments
-
stress,
friction
and
mass
can
be
brought
into
the
illusion.
This
technique
has
been
successfully
used
to
color
action,
and
done
poorly,
can
provide
a
comedic
quality,
if
you're
into
that
sort
of
Benny
Hill
thing.
However,
very
convincing
single
frame
camera
tricks
are
possible
if
executed
skillfully.
