MB Tutorial Part 46: Constraint Tracks Video Lecture | A Complete Course: Motion Builder - Professional Skills

alright in this lesson we're going to
take a look at how we can animate the
timing and blending of constraints using
the story window and constraint tracks
so let's go ahead and have a look at
what we have in our scene we jump to my
producer perspective window we've got
our ninja character and he goes to this
nice long animated sequence where we
have a couple of cameras animated and
what I'm looking for is to take this
second camera over here and I want to
constrain that to an object inside the
scene to create sort of a bullet time
pad around right here during our bullet
time kick
now given I could use turntable but as I
mentioned earlier sometimes if your
camera is that an extreme angle you
might want to use you might not not want
to use turntable because the disk of
rotation of turntable might be I will be
at that rotation as well right we're
going to use a constraint to make this
effect work but we're going to need an
object to constrain to what I'm going to
do is bring a null into the scene
constrain the camera to that null and
we'll use that constraint as a way to
spin the camera around so first thing
let me bring a null into our scene I'll
go into my asset browser and under
elements we'll just grab it null drag it
in like so and first thing let me scale
it up because it is rather small and
rather than physically try to move it
around to get it positioned right in the
middle of the action for this particular
example i'm just going to alt drag it
right onto the cameras interest like so
we'll select a line translation all and
that'll snap it right to the location of
the cameras interest which if you
noticed is pretty much right in the
middle of this kick and should work just
fine so now we need a constraint in
place to constrain this camera to the
null so under my asset browser
underneath constraints I'm going to grab
a parent-child constraint and drag it
into the scene now for more information
on how constraints work we actually have
a vtm at 3d buzz calm over constraints
in MotionBuilder so be sure and download
that if you if you need more information
all right so I need a new window to
access the settings for this constraint
so under window let's add asset settings
and I'll just go under my scene browser
and double-click my parent child
constraints make sure to unlock the pain
first and we'll lock it back so I don't
accidentally deselect it and we'll
resize it a little bit so it's kind of
out of the way now the parent in this
relationship is going to be our no
because he is going to force rotation
upon the camera so the camera is going
to be the child now I need to move the
camera into the exact location that I
want it to be when the constraint goes
active so what I'll do is I'll
right-click make this camera current and
really all I want to do is just zoom in
a little bit maybe rotate up to a higher
angle maybe something right about here
so we have a kind of a nice above look
now in order to move that camera around
I needed to have animation active over
here so it looks like i just placed a
keyframe so just be aware of that for
this particular case i'm going to go
ahead and switch off auto key and then
we'll position our camera one more time
without placing any kind of a keyframe
so just be aware of that if you've
activated auto key you're going to want
to switch it back off for just for a
moment now let's come in here under our
constraint settings and I'm going to
snap this constraint into place what
that will do is activate the constraint
but keep the initial offset between the
null in the camera basically it keeps
the camera from jumping to the exact
same location as the null with that i'm
done with this window so i'm going to go
ahead and close it let's go back to our
producer perspective window and there's
a slight problem with this animation so
let me play it back and Joel why don't
you tell me what it is and it's no
longer panning the camera is no longer
moving exactly this camera is now locked
into position the interest is moving
fine but exactly but the camera itself
isn't why do you think that is well the
constraint is applied to the camera the
whole time exactly this constraint is
always active right now so would it be
cool if we had a way to turn that cat
that constraint on and off that would be
nice yeah that was my goofy cheesy segue
into the constraint track
oh yeah okay so the first thing i want
to do though is I'm going to switch off
animate for this particular camera track
i'm going to right click insert a folder
let's rename this folder to camera
animation just to clean things up again
i can't type right now so that's okay
camera animation and we'll drag both of
our camera animations up inside of that
and minimize it to get it out of the way
now i need access to that constraint
that i just put in so here it is inside
of our scene browser and check this out
i'm just going to alt drag it over here
inside of story it automatically gets
its own constraint track and voila now
watch this just something a little
interest so something interesting for
you to kind of try to wrap your head
around if I rewind the animation and hit
play look at this
and then pal the camera snaps while
during that clip it's constrained and
after it leaves the club is no longer
exactly this kit this particular clip is
kind of like a boolean it's on or off as
long as the timeline indicator is inside
this clip the constraint is active as
soon as timeline goes outside this clip
constraint deactivates cool so now we
have a way by which we can take this
constraint we can scale it to adjust how
long it lasts and we can slide it along
the timeline to control when it happens
so now we have complete control over
when this constraint takes place so what
I'm going to do is open up the ninjas
animation and will find this one little
slow motion section let me go ahead and
shrink this up a little bit to make some
room right about here should be our
bullet time clip so let's scrub forward
and just double-check that right here he
goes into bullet time that is exactly
the time that I want this constraint to
be active so for now let me take the
constraint and I'll just scale it down
and make it kind of small and we'll zoom
in here on this clip I'm going to set
the timeline indicator right at the
beginning of this clip and then just but
the constraint right up against the
timeline indicator slide the timeline
indicator to the end of the clip and
again just scale out the constraint so
that now we're only constrained during
the bullet time kick so you can see it
the camera let me zoom in just to make
sure everybody can see that nice and
easy right as we go into bullet time the
camera jumps
you
and then it jumps back as soon as it
fades back out very cool so let's go
ahead and animate our null real quick so
that we can engrave our bullet time pan
around effect so for now let's go ahead
i'm going to take my constraint track
and we'll just scale it up a little bit
we don't really need the weight anyway
and that should be plenty of room i'm
going to grab my null and just alt drag
it down inside of story so it gets its
own animation track automatically also
i'm going to switch auto key back on
because that'll make this particular
task a great deal easier now let's bring
our timeline indicator to the beginning
of this constraint like so i'm going to
activate my animate button i'm going to
place my initial key frame then I all I
need to do is just slide to the end of
this constraint and we just need to
rotate the null around so will grant
send it to about here let's get our
rotate tool out and I'll just rotate
around you see a keyframe was
automatically placed let's bring it all
the way around about like so that'll
look that looks good now let's go ahead
and switch off animate and we'll scrub
back through we can see the camera
rotate around our character in a really
snazzy kind of bullet time way now let's
go ahead and make the camera active and
see what that looks like so the camera
is now current let's uh scrub acted
really quick I'm going to come through
really slow the camera snaps in we
rotate around in bullet time
very nice very cool but there's still a
problem snapping snapping we duh mean
that is so it's cool that we can do this
but it's very ugly to have the camera
just pop right up here would it be nice
if we just fade right into this that
would be nice another cheesy segue and
it's gonna fade in and fade out so what
I'm gonna do is take my fate in handle
of this constraint track let me kind of
scale this up so everybody can see it a
little easier this little yellow Faden
handle I'm just going to drag in like so
and this will control how we fade into
this constraint so now it's no longer
just snapping on watch this we gently
slide over into position to the
constraint smooth so let's go ahead and
also stayed out of it as well and we
fade right back out of it cool so let me
go ahead and I'm gonna switch to models
only and I'm going to rewind this
animation and we'll watch it all the way
through with this camera so our ninja
comes through running we watched him do
his back flip he goes into his crouch he
starts kicking one kick and two kicks
and then right here we're gonna go into
bullet time and
oh babe addresses and everything's all
set so really with that we've shown how
we can take constraints and animate
their time on and off how we can fade
into and out of them all using the story
window so with that that's going to wrap
up this lesson thanks a lot everyone