hiya James we're from here for plugging everything and so we're gonna be talking
about how we can animate physics by expressions if you're anything like me I
can't animate for peanuts and so expressions really help me with that
especially physical based expressions such as balance elastic etc so in this
example I've just got a ball that drops and it's got its default linear ease
which is boring so I just select those and apply the bounce expression for ease
and whizz this is a NAME YOUR OWN PRICE script from aescripts.com with the original
expressions I believe based on Penner's easing expressions which you can find
more about here at Robert panakam slash easing so we simply select keyframe
apply bounce out and been there we go we've got our ball bouncing the great
thing about this is that just so we wanted to drop the ball from a little
bit higher we can simply increase the height of the drop and it updates
automatically which is great very easy to iterate so that was very easy let's
try a more complex example we're going to animate some shapes using elastic
instead of bounce I'm just gonna create a new solid and add an ellipse to that
and just scale it down to 90% then change its opacity to very low this is
just a guide for me because I want to draw essentially a bit of rope that's
been stretched all the way back so two points and then vertex in the middle we
drag that all the way down and I'm gonna draw this at its starting point where
it's been stretched back as far as it can go and the reason I had the circle
is because I want it to emulate the look of a circle at this stage so we go
content shape path keyframe that then I'm gonna come to four seconds and this
path here I want it to essentially be at its resting state at the start it's been
stretched and then once it's stopped wobbling comes back to this resting
state issue I currently have is that the handles are too long at the end and so
all the animation looks good at the start at the end these handles shouldn't
be as long so if we just come to the second keyframe we can just make these
shorter and then we'll get a more natural-looking animation towards the
end we want to use the elastic expression which overshoots the end of
your animation and shows a bit more so what we need to do is then come to
say eight seconds and draw our overshoot animation which is very easy it's
essentially the same as the first keyframe but just all the way at the
other end rather that's kind of what we would expect if you slung a slingshot
and then it went all the way up here and then it would come back to its resting
place so I'm pretty happy with this animation if we were to apply say Expo
in and out or expert out to this it would say looks like you have a mask
path selected so to apply is in ways you need to use the curvaceous checkbox
that's because instead of just numbers were actually interpolating between
paths and that's going to work that's now applied the expert out
however curvaceous doesn't work for elastic or back and that's because it
has that overshoot and it doesn't know that you if you've supplied it or not we
have supplied it here there overshoot but it doesn't know that so we need to
cheat this a little bit we need to grab comp one actually before I do that I
just click that and remove that expression I just want the linear ease
drag comp on into a new comp go time time remapping then come to our resting
point set a keyframe delete the last keyframe and now we don't need this
curvaceous because now we are dealing with number data here instead of paths
and we go move a curvaceous get elastic out now if we play that back it's not
going to look very good and the reason for that is if we actually display this
if we visualize what's going on here we can see it's too extreme the amplitude
is way too high so to set this up I'm just going to add two sliders the first
one's gonna be period and the second one's going to be amplitude and then if
we go into the expression itself you can see we've got the period here which is
point eight one I believe that's usually a value between zero and one and that's
the time distance between the keyframes and the amplitude is how far it's going
to shoot so if we have these both set to zero I don't know what's going to happen
actually okay it's just the default animation make the period like two point
eight one and we can again visualize these but the amplitude is still zero
let's that up to say two so there we have our
wobbling animation it's a little bit boring though so we might want to
increase the amplitude and if we go too high we'll see we get this clipping
where it's gone past eight seconds remember we don't have any animation
past eight seconds so that's it's just gonna be blank there so we can't go too
high but you can if you want you just got to make sure you've got the
overshoot animation for it to display I don't want it to be that high I'm going
to try that your six the great thing about this is this updates if we make a
change we can see that same with the period but I think the about your point
eight one suits it I think this is looking pretty good but I wanted to sort
of shoot out at the start quicker and what we can do to do that is instead of
having this resting point at exactly the middle we can speed up the start and
then have the end slower but now that we've changed the resting spot to be
three seconds 15 frames we need to update that here otherwise the resting
spot is going to be you know not halfway so we just click on this and make this
three fifteen so now it's a bit bounce here at the start the other thing we
want to do is probably turn this into a guide layer so that we can't see it also
I believe the stroke looks better on Sena mayshen using a round cap rather
than a bite cap that's looking pretty good I still think the handles at the
resting spot are too long and so it's making it look a little weird so I'm
just going to shorten those I think that looks a lot better in the final result
that I've got I've added a plugin that coincidentally plug-in everything makes
called path visualizer to display the handles and the vertices and then I've
just animated a very quick pen tool animation to show that the pen tool is
what's pulling back the elastic and and loosing it and then I simply just looped
it so that it can play forever so make sure you check out plugging everything
comm we've got heaps of cool plugins some of my free most of them
aren't but that's how it can afford to sustain ourselves but thanks for
watching and I hope you create something cool with expressions
you