11secondclubbers, welcome!!
One of the animator’s goals is to
make the animation believable in the eyes
of the viewer. An example of that is that the emotion portrayed needs to
look sincere. Another is that the animation needs to abide the laws of physics
of the world it’s in. I’ll be talking about the latter, about technically
correct, consistent, animation, physics and whatnot.
This might sound a bit daunting to
the beginning animator, but it’s actually just some general rules that you need
to keep in mind. The rules are easy, but they are easily overlooked and
sometimes harder to implement. My own goal with this piece of text is to
provide you all with a teeny bit of awareness, and I hope that will make your
animations that much better.
Also worth looking into: Suspension of disbelief
Intro
to consistency
Maybe I'm just a geek, but I like consistency.
I like the fact that if you know the weight of an object, you can calculate the
time it takes for it to reach the ground from a certain height (leaving density
and air friction out of the equation). I like the fact that when a ball bounces
(up/down), it will leave the ground with the same speed that it approached the
surface (provided that the surface is flat, inanimate and isn't sticky).
I like the
consistency, the predictability, the logic. I like the fact that if you follow certain rules and logic, your
animation will have a higher chance of being convincing, isn't that just
great? Reading this piece is but a small price to pay for becoming aware of
such logic, right?
Okay! So we've
established that I'm a geek, but have I convinced you of the importance of
consistency in animation? I bet not! Next up I'll cover some of the bases you
need to cover when working on an animation and I'll add examples to the mix too. I'll not hand every
bit of knowledge to you on a silver platter though, if you don't understand
something try to research it or ask questions, try to truly understand it! Good
luck! :)
(Exceptions to these pieces of logic are dealt
with later on in the article.)
Gravity
/ Weight
I'll spare you the
big scientific explanations, but here are just some basics you need to be aware
of.
Gravity is a force
that acts on anything that has a weight and a volume. Gravity is "a natural phenomenon by which physical
bodies attract each other with a force proportional to their masses" (according to Wikipedia).
Seeing as the mass of a planet is a
constant, it depends on the mass of an object what the gravitational effect will
be (the heavier the object, the bigger the force will be).
During an
animation, the mass of the object and the planet won't change, they are both
consistent. The force between the object and planet will be consistent! Exceptions
aside, gravity and weight are predictable and consistent. They won't suddenly
change unless there's a third party in play. (Like a magnet, a huge blowing fan
or addition of helium).
EXAMPLE:
Anatomy of a bouncing ball (part 1)
This is the
exercise that every animator has to do, for a very good reason, but
unfortunately not every animator is confronted with the truth behind this. Did
you ever try to understand the logic behind the bounces? What makes the bounces
get smaller? How fast do the bounces get smaller?
Did you ever
notice that the arc of each bounce has the same width/height aspect ratio? That
they get proportionally smaller?
It's all about
gravity! Gravity is the steady force that attracts the ball to the ground.
Gravity is steady, that means that with each bounce, the bounces get
proportionally smaller, proportionally being another key word here related to
consistency!
EXAMPLE: Floatiness, a problem that pretty much all of
us animators have encountered at one point or another. So if you get this
critique on 11secondclub or from your peers, this is what it means: the problem
is that during the animation, the object seems to be able to stay in the air
longer than its weight and force should allow. It's not consistent with what we
expect. It's not consistent with the weight of the object or with the force (whether
it be gravity or other).
This might also
occur the other way around, the object seems to be in the air shorter than its
weight should be able to allow.
EXAMPLE:
a more problematic encounter with floatiness:
A while back I saw
an animation of a balloon filled with helium. The balloon is let go, it rises
until it hits a plateau, but it bounces to the side of the plateau and it
starts rising again. So there are two instances where the balloon starts to
rise in this one animation. The problem was that the balloon sped up faster in
one occasion than the other.
The thing that the
animator should have paid more attention to is that the weight of the balloon
and gravity will remain the same during the whole of the animation. So this
means that the balloon should gain height and gain speed at the same rate in
both occasions.
Of course exceptions
can be imagined, like a fan below the balloon, but there was no fan in this
particular animation, so it was a mistake.
Force / Energy
Energy, another
consistent attribute in animation! No scientific explanation here, just a
healthy dose of logic.
If you reach out
and put your fist out reaaaaally slowly, you won't give someone a black eye now
would you? Basically it's a matter of keeping track of the energy that is
put into an action, and comes out. Those values should be (about) equal in your
animations (again, exceptions aside).
EXAMPLE:
It's bouncing ball time again! (part 2)
After a nice big
bounce, the ball gathers downward momentum as it speeds towards the ground.
Once the ball hits the ground that downward momentum is instantly converted to upward momentum. So the speed at
which the ball was approaching the ground then becomes the exact speed at which
the ball moves up and away from the ground. It steadily (, proportionally,
consistently!) loses energy again due to gravity until it has no upward energy
anymore and starts moving down with the energy of
the gravitational force.
Also notice that
when your bouncing ball moves sideways, it only slightly loses sideways
momentum due to air resistance. After it stops bouncing it'll lose sideways
momentum faster due to friction with the ground.
If the ball hits a
wall, the sideways left momentum becomes sideways right momentum without losing
any energy, it just gets changed in direction.
EXAMPLE:
Hitting an invisible brick wall, or the likes
Bit of a tough one
to explain, but a problem I've encountered in my own animations a couple of
times. Let’s just take the arms in a walkcycle as an example. The arms swing back
and forth during a walkcycle. They gain and lose momentum like a bouncing ball
pretty much, except that most of the force comes from the muscles instead of
from gravity. Sometimes it happens that the arms seem to hit an invisible wall
in your animation. It feels like they should swing trough more, instead
something invisible stops it from doing so. This means that the energy is cut
short, the arm loses momentum unproportionally, too suddenly. It needs more
follow through!
Related to this is
the changing of amounts of energy in the middle of an animation.
EXAMPLE: The
character jumps and after the apex of the jump, the return journey towards the
ground is much faster than expected. It's like he's sucked towards the ground
suddenly instead of it happening steadily.
EXAMPLE:
Expectation of the viewer
If you see a big
guy, like the Hulk, pull his arm back into a nice big preparatory swing, we as
viewers start anticipating a big blow, right? Well let’s say he hits ye ordinary
window with that big swing of his, but he doesn't manage to break the glass,
well the glass better have some really good reason not to break! Now this is an
exaggerated example of course, but it illustrates that the suspension of
disbelief of the viewer can be broken by bad logic, so use this power well. Ask
yourself if the result of the animation is what is logically to be expected.
A simpler EXAMPLE
of this would be if the spring that is pushed down to half capacity, it
won't spring up with the energy of a spring pushed down to full capacity.
Exceptions
(full of EXAMPLES)
There are a lot of
examples of exceptions to these little pieces of logic, but these examples are
the result of specific choices made for the animation. Some examples:
Sometimes it's
necessary to break gravity, for instance when blowing up an aunt (Harry
Potter reference) or when your character is in a spaceship made by
Bulma (DBZ reference). But that doesn't mean that animations aren’t
consistent! They
need to be consistent within their own context (very important!).
Another popular
exception is the Warner Bros logic of hanging in the air before realizing there
is no ground to walk on, then wave, and only then start falling. This is
obviously a stylistic choice. But after starting the fall, the speed of the
falling needs to be logical and believable.
EXAMPLE:
Animation style
Another example
where it's important to be consistent within the context of the animation is
with stylistic decisions. The snappy timing in the below example isn't
realistic, but it is consistent! What this means is that they've consciously
adjusted the physical rules of their world, but the rules of gravity,
weight and energy do still apply.
Burning Safari:
Conclusion
Well, the point is
that we need to do everything we can not to break the suspension of disbelief
of the viewer. It needs be believable. To consciously try and make it
believable we pay heed to the rules of gravity, energy, weight, etc, etc. Even
if the style of animation is different, or the situation you're animating isn't
consistent with real life, it still needs to make sense, be consistent within
their own context.
Yep! I think
that's about it. I hope I included enough examples, haha.
I know the article
isn't structurally coherent, sorry!
Any questions are
more than welcome! Thanks for
reading! J
hello,
ReplyDeletecan you please discuss timing a little more...?? you wrote here that the ball takes off at the same speed at which it hits the floor...so my trimmings are 0-10-20-28-36-42-48-52-56-58-60-62...the timing is still not right.. specially towards the end where i end up with two frames...i cant figure out how to correct it..
Hey there anonymous person!
ReplyDeleteI made a bit of a long reply, but blogspot didn't accept it, so I put it on google docs for you to read.
https://docs.google.com/document/d/1y0-_Bp6fMBSa0-7YuaLdteejs5s_VGDobXMBAgzdkUs/edit
I hope it helps! And if it didn't, well then you know where to find me!
yeah i did a lot of search on timing..and i coudn't figure out the timing..i always thought there had to be an even deductions to maintain time ..i did the calculations and now i get it..thanks... :)
Delete