MB Tutorial Part 22: Simple Constraints Video Lecture | A Complete Course: Motion Builder - Professional Skills

all right in this lesson what we're
going to be talking about is simple
constraints in fact Zacks going to run
through all but two of the simple
constraints we're leaving two of them
the range constraint in the mapping
constraint for a later vtm that's going
to be constraints number two and we're
going to be getting into things just a
little bit more in depth in what you're
going to see here but he's going to walk
through all the other constraints as
well as give some very basic examples of
how they're used but by the time he gets
the end of them you guys can be able to
use all these simple constraints with
absolutely no problem at all alright
cool well let's go ahead and get started
so if you come over here to your asset
browser when you first start off you got
a constraints folder and if you click on
this down here in your window underneath
you're going to have all of these simple
constraints listed okay now of course
here are the mapping and range
constraints these are the only two we're
not going to cover all of your other
simple constraints are the three point
constraint rotation parent-child I K
position and rigidbody all right and I
will throw in don't be afraid to get in
there and play with the mapping and
range right now the mapping is really
cool where it can take a parent-child
relationship and map it to another
parent-child relationship which is
really neat stuff especially when you're
dealing with scaled animations and
you're bringing animation and from one
hierarchy to another if you will and in
the range as well it also gives you some
pretty interesting control absolutely is
going to allow you to do things like
take your hips and constrain them right
in between the feet of your model but
once again we're going to get it all
that kind of stuff in a more advanced
lesson exactly so let's go and start out
zag with the position everybody knows
translation absolutely translations one
of the most basic things in 3d is just
moving your objects around but first
before I do anything it'd be nice to
have some objects to use so I'm just
about some cube out some cubes
everybody's gonna have to get used to
seeing cubes I'm going to be using them
a lot here in the next few lessons but
don't worry it's not going to stay cubes
forever because like we said at the very
beginning of this vtm we are going to
turn around a little bit later on and
put all this to good use with our alien
absolutely so let me go ahead I've just
duplicated this cube off a few times so
now I've got three cubes in the scene
and let me go ahead I'll come over here
to my navigator my scene browser and
I'll open this up so we can kind of see
what's going on and the first thing I'm
in right now well before you go over
there doing this question
go to the navigator you'll notice in the
browser that Constraints is not
expandable meaning that currently there
are no constraints in our scene
absolutely we've yet to drag and drop
any into the scene exactly so keep an
eye on that constraint setting as zag
drags and drops the position constraint
into the scene look at that now we can
expand constraints and if we want to we
can see that there is the position
constraint up underneath it all right
now as I said before in the introduction
simple constraints are like
prefabricated constraints inside of
MotionBuilder basically all of the work
of connecting one attribute to another
has been done for you so now you take
your objects and you drag them into
these open cells and that determines
what your constrained object is and what
sources that it might be deriving its
translation rotation or scaling from
exactly and over in the constraint
settings window area you'll notice it's
divided up into two area the areas the
area on the left-hand side gives us
basically parameters that activate our
control activating and locking this
constraint itself while on the right
hand side we have cells as Zack was
mentioning a second ago which allow us
to actually assign what objects are
going to be constrained to and constrain
ease if you will absolutely our
constraint ORS are constraining that's
much better
all right so uh I'm just going to go
ahead and lightly go over these controls
because I'm going to go over them a lot
more in depth as I use them so just real
quick as an overview we've got a used in
story button which is grayed out right
now this is because we're not using any
stories we're going to be going over
stories in a separate vtm so right now
would be irrelevant to go over them
exactly so that's going to remain
disabled the entire time exactly now we
also have an activate uh button and what
this is going to allow say it's a
checkbox I'm sorry button now if we
check this is going to set our
constraint to being active right now we
have nothing set up we have nothing
constrained so it's not gonna really do
us any good lock I'm gonna get into it a
few moments actually when I start to use
actually no attack before we really
start digging through this this is one
of those really weird situations where
it almost helps for them to see go ahead
and set up to object you're absolutely
right let's go ahead and do this I'll
start with cube one now you'll notice
when I double clicked him to select him
my settings area over here changed over
to the settings for that cube so what
I'm gonna do is come over here and
double click my position constraint and
I'm gonna lock my settings area so that
it's not going to change over and I can
select whatever
I want good workflow so now I'm going to
select my cube and I'm going to alt drag
this middle cube into my first cell
which is distrained object yeah
constrained objects are constrain
e-exactly so now we need at least one
constraint or so I'm going to select
just one of these guys out here as a
source object I'm gonna alt drag him
down into this cell drag and drop is
very very nice now you'll notice that we
suddenly have source two that became
available meaning that we have the
ability to go in there and take a
constrained object and constrain it to
multiple objects at a time when they use
in the position constraint right this
won't be true for every single
constraint that we're going to be using
but the position constraint will allow
you to constrain one object to multiple
positions basically it'll it'll make
your constraint find a midpoint between
several objects exactly now right now if
that goes in there and moves the
constrain or cube around which he's
going to do now you'll notice that the
constraint object the middle cube does
not move exactly nothing's going to
happen right now because our constraint
itself is not active this checkbox has
not been checked now before he actually
checks it I will say those of you out
there familiar with most 3d applications
know that when you use some sort of
position constraint that what's going to
happen is you're constrained object is
then going to immediately snap to the
constrain or object because basically
it's going to receive that same
translation data right I really I don't
want to use the word snap too much
because we've actually got a snap button
here which has its own function so you
could say that it's just - yeah as soon
as we activate this we're going to get a
warning that says the objects will move
to accommodate the constraint and of
course we're gonna click OK and it looks
like our constrained object just just
disappeared
that's not actually what happened it
just inherited the translation data of
our source object exactly so basically
they're both in the exact same position
exactly exactly so uh I can move this
guy around and removing both of I'm
moving both around the constrained
object is flowing right along but if
you've got several objects in the scene
and you're trying to constrain position
between the two you're very rarely ever
going to want their positions to become
one right I mean unless you're just
using these as actual markers that won't
render out typically in a render you
don't want two objects to take the same
space so what we can do let me
deactivate my constraint and just take
moment move everything pretty close back
to where it was just kind of reset my
scene what we can do is we can use the
snap button when I click snap it looks
like nothing happens but the active
button did become checked
notice how we did not get the dialogue
warning us this time that the
constrained object was about to move or
possibly move to accommodate the
position required by the constraint
absolutely because when you use snap
that's the whole point no motion is
actually taking place what you're doing
is you're establishing an offset for
your constraint so now what we've got
here is our constrained object has this
given offset with our source object and
now we move our source the constrained
object comes along keeping the given
offset maintained throughout now of
course what's really nice is we have the
ability to grab the constrained object
and move it as you can see here now the
constraint scenario still exists as you
see here exactly so we can actually
reestablish this offset whenever we need
to in this case just by moving our cube
but this could be bad we may not want
our animator to be able to accidentally
move the constraint object and that
brings us over to the lock check box
exactly you might uh when you're using
when you're building your scene when
you're animating you might spend a long
time getting your constraint set up so
that you've got very precise locations
okay if you're doing you're working with
maybe some kind of piece of 3d machinery
and you got pieces that interlock and
everything has to be just perfect you
don't want your constrained object to
slightly move out of sync with the rest
of your scene right so in this case
we've got the lock checkbox if we lock
this guy real quick I can just show you
now that he's locked I come over here to
drag to move him and I get nothing the
translations because that's what the
position of constraint controls is now
long exactly and even if I come in here
to rotation I can still rotate because
this is just this constraint is only
involved with position alone right so on
now I can come in here and I can
translate my source object and of course
now the constraint object will come with
me but I cannot move the constrained
object itself it now moves solely based
on the position of my source okay and
then there may be a time when you at
this point would need to take the
constrained object and get rid of that
offset exactly so I mean perhaps in this
case we decided we don't want that
offset after all
what we can do is we've got a button
over here called zero if we click that
what it does is it removes our offset so
now our cube our constrained object has
now gone to the exact position of our
source object once again just like when
we originally activate her a constraint
all right very nice so go and undo that
and line them back up you have another
question for you that some of our
beginners out there may be thinking
about actually I'll do you want a little
a little better just to kind of work
ahead a little bit all right so
everybody everybody who's any home right
now is going what did he just do that's
what I'm about to go into you okay the
white slider we have a slider down there
that has the ability to be keyframed as
you can see now a lot of people may
think of the white slider as so does
that mean well first of all actually you
know exact before McGee you got it I'm
writing I'm going to do is he's going to
bring another object in so now the
center cube is now constrained between
both source 1 and source 2 so if you
take source 2 and moves it around you'll
notice that the cube is going to
maintain a 50% relationship between the
two so he's going to activate it and
then we'll head it that was great I love
it so let me go ahead and uh in this
case we need to actually do a snap
because of course there is going to be
an offset in place okay oh I'm sorry
everybody forget you this were my uh my
brain problem right there what I need to
do is take my weight and set it back up
to 100% that was that's what I get for
showing off yeah so anyway before we
could even get into the weight thing let
me go ahead and just kind of rewind
we've got our constrained object and now
we have two sources like I mentioned
earlier in the case of the position
constraint you can have as many sources
as you want and what's going to happen
is you're constrained object is going to
maintain a midpoint location right in
between your source exactly so now that
I've got this all set up and I activate
this constraint and I get my warning
that objects will move now when I move
either one of my sources my constrained
object will always stay directly in
between them ok now this brings us down
to an interesting thought about the
weight some people may be thinking of
does the weight allow me to blend from
one cube over to the other in the
sir is no as you just saw Zack
demonstrate for a second ago
what it actually allows us to do is
determine how much of this particular
constraint is being applied to the
constrained object at the moment why
right now it's at a hundred percent so
it's receiving a hundred percent of a 50
percent division between the two whoo
that was a ooh man that hurt you see
what I'm saying though yeah actually
that's what I was trying to demonstrate
earlier really I promise
uh so as he goes down there and he takes
that weight and he starts to drop it
like this the cube then goes back to its
starting point as it goes back to its
original pre constrained position
exactly so it's not like it's blending
between one cube and the other now Zack
is there a way if we wanted to set up
some sort of scenario where we could
have the cube blend from one over to the
other based off of two constraints
absolutely uh but like you said right
there actually you just gave the answer
away we need it to be two constraints ah
because right now what we've got is two
sources but they're in the same
constraint so the location that we've
got here that we're actually blending
right now with our weight that is just
like I said a single constraint what we
need to do if we want to blend in
between these two positions is have two
constraints so what I'm going to do real
quick is just drag that cube out now
what I did was I just removed one of the
sources so what happened is our
constrained object went right to the
location of our source because there was
no offset that was done with you just
clicking activate that time right so
this time I'm going to drag another
position constraint into the scene and
once again we get an entirely a new
constraint to enter in our window here
and we have no constrained object and no
source first thing I'm going to do is
take this cube here and set it up as our
source now over here in my navigator my
scene browser I'm going to take my
original cube which is my constrained
object from my other constraint and I'll
just drag him directly over I don't have
to use alt drag because I'm not pulling
from the viewer and drag him to my
constrained object and then activate
this constraint and it comes directly
over here now you just saw it snap from
one over in one location to the other
the reason for that is here on my second
constraint position number one I have
100% weighting okay what's happening
right now is MotionBuilder is saying
okay you have 100% waiting on this
constraint
so that must mean that you want you're
constrained object to be completely over
at this source officers actually there's
actually a priority that is followed
here when calculating the constraints as
well going from top to bottom right
constraints are applied from top to
bottom with the bottom constraint being
applied last exactly so what happened is
it did indeed get constrained to the
first one but then the last one which
was that a hundred percent a guy
constrained over to a hundred exactly
and now a lot of people who come from
other backgrounds other programs I like
Maya if you point constrain an object
between two other objects what you will
get is your constrained object will snap
to a midpoint in between the two exactly
then you can blend your two separate
weights in between it's a little bit
different in MotionBuilder in that now
we're taking the weight of our of our
second constraint and we have a full
100% control there so if we have 50%
control over this constraint if we drag
this down to 50 we're now halfway
between our two source objects again and
this is because of in a sense the order
of constraint calculation exactly you
can think of it this way if we take our
second constraint here if we have it at
a hundred it's all the way over here at
this source but if we set it at zero
that means since this constraint is
still at 100% it's going to be dragged
all the way over here conversely we
could come back to our original position
constraint and drag it down to zero as
well and our cube goes right back to its
non constrained position you got it so
we can set him up to a hundred and then
based off the weight of our second
constraint we can blend from one
constraint to the other okay that was
just beautiful
that was nice it was a very good
description of the position constraint
so Zack let's go ahead and move on now
all right so let's do it I'm going to go
ahead first of all I'm going to delete
these constraints out and it's going to
do make sure you want to delete it
remember you can't undo deletes in
MotionBuilder so when you are deleting
something out of your scene browser make
sure that's what you want to do click
yes to get rid of it well right click
and delete the second one as well once
again I'm right-clicking over here in my
scene browser to get rid of these and
everything pretty much goes back to
where it was before I constrained it
okay so now I'm going to go on to the
next constraint I want to demonstrate
which is the rotation constraint this is
very similar to the position constraint
and that when you open it up you have
one constrained object in one source
unlike the position constraint now
we're just covering rotation position is
not a factor in this constraint what
exactly so don't expect to see your Cube
snap or move if you will to another cube
he's not going to jump exactly be
receiving rotational information exactly
so first of all I'm going to go ahead
and take my original constrained object
the center cube and I'm going to alt
drag it from my scene into the
constrained object cell I'm going to
double click on the the source that I
want to use and once again I'm double
clicking and since I've got my Navigator
locked then my settings area is staying
constant with my constraint so I'm going
to alt drag it into my source and then
when I activate this
I'll get my message that I my
constrained object is about to move to
accommodate of course you don't see any
jump here because well because I've yet
to rotate these guys yeah well first of
all you won't see a positional jump
because it's a rotations constraint and
since you've yet to rotate anything
right you don't see any rotate there's
gonna be no change whatsoever and to go
ahead and kind of demonstrate what I
mean by saying that translation is not a
factor let me just go ahead and
translate our source object with our
positions constraint when we move this
guy our constraint object came along but
now as you can see nothing happens when
I move this guy around that's because as
I said this rotational constraint is
strictly based on rotation so let me go
ahead and we'll select rotation and I'll
just go ahead and freely rotate this guy
around and you'll see that our
constrained object matches his rotation
perfectly exactly now of course you
notice we have a snap button just like
we did a few minutes ago in working with
the positions constraint and that is in
case we want to have an offset already
in place so Zack is going in right down
and pre rotating our constrained object
and then he's going to reactivate by
clicking the snap to record that offset
there you go now it's going to maintain
that so basically we're just adding this
new rotation data on top of the rotation
that's already in place on the
constraint cube exactly our constraint
object is still matching the rotation
but it's in a relative sense now based
off the offset we established very nice
so uh and once again just like with our
other constraints we have a weight
slider that we can use to adjust the
weight between our original rotation and
our new constrained rotation okay but
unlike the positional constraint we do
not have multiple sources
that's right we're only allowed to
constrain rotation with this particular
constraint from a single source to
something keep in mind okay so I'm gonna
go ahead and delete this guy and of
course lock works this important Allah
works everything works the same you're
gonna find that lock active snap and
zero gonna work the same pretty much
throughout until we get to the relations
and expressions constraints but we'll
get into all those because when we get
to those we change everything yeah we're
gonna we're gonna hurt some people's
heads with those yeah not not this
b-team not alright alright if you say so
I'll be nice so uh what's he let me go
ahead and I'll just delete this
constraint out that's a good example of
what you can do with a rotations
constraint say yes to that and let me go
ahead I'm going to take all these guys
I'm going to hold down my spacebar and
select all of them over here under my
transforms I'm just going to zero all
these guys out and that'll zero out all
their rotations alright so what are we
gonna look at next well next we're going
to look at the three-point constraint
woozi it is a little fancy actually and
the first time you see it it's downright
scary what it does is so powerful
absolutely basically if I just try to
tell it to you in words is what makes it
kind of sound a little intimidating what
we're doing is we're taking a
constrained object and we're
establishing its rotation based on the
translation of three other objects you
got it a lot of you the first time you
hear that are going to say Zack why in
the world would we ever want to do that
well MotionBuilder has really good
support for motion capture data hmm
obviously obviously so if you have
somebody with a motion capture rig on
and they have a sensors all over their
body those sensors are not detecting any
rotational data they're only detecting
translation points exactly so what you
can do is you can use the location of
translation points or your sensors to
derive rotation for another object for
an example if you'll just uh kind of
follow along with me before I
demonstrate let's say we have a model of
a forearm piece perhaps like a computer
that strapped to the rest of the
character aliens wrist computer well I'm
not saying that perhaps but that would
work just fine would work just fine for
this example but in this case we're
going to want that wrist computer to
always stay in the
or arm area of our model of our
character right so we've already got
some data information then what we can
do is we can use a three point
constraint based off the wrist the elbow
and the shoulder to keep that wrist
computer rotating in the minute proper
rotation to match up with all of our
joints all right
and once again I said a key word in
there that some of you might have missed
this uh this constraint will only cover
rotation you're about to see that it's
not going to cover translation at all
but we'll get it out here in just a
second first of all let me kind of set
up my scene a little bit to make this a
little easier to understand I'm gonna
duplicate this cube drag him out a
little bit like such and what we'll do
is we'll assume that this scale him up a
little bit in Zed as well all right okay
we'll assume that this piece here is
kind of like our forearm computer or
something that's going to be strapped to
the forearm of our model we'll assume
that this point let's just say it's our
forearm and that's our yeah either way
is going to be it's going to work just
fine for this example okay we'll say
that this would be this would represent
the sensor data from our shoulder this
would be from the elbow and this from
the wrist all right if everybody follows
along with that this is going to go just
fine if you miss that this might hurt
your head a little bit so rewind the
video if you need exactly so we'll start
off with our constrained object which is
going to be our model itself our forearm
in this case so I'm going to alt drag
him from the scene down into his
corresponding cell now our next cell is
the origin now that sounds a little
funny at first you might be wondering
what is going to be our origin your
origin is going to be the pivot of your
constrained object where is it going to
be rotating from in this case we have a
forearm so we're going to be rotating
naturally from the elbow okay
so we'll take this the cube that
represents sensor data from an elbow and
we'll drag it into the origin slot now
the target is where it would be rotating
to which buzz would be a ribs very good
just making sure you're paying attention
oh yeah okay so I'm sorry couldn't help
myself
Zack caught me looking the other way
absolutely so what we're going to do is
we'll just take the sensor effort so to
speak that's going to represent our
wrist and we'll drag it down into the
target and now we have an up factor
basically
what part what sensor is going to
designate with what is always acting as
an up Vector what's always going to be
pointing up so that will naturally be
the shoulder in the case of a forearm so
let me go ahead and we'll alt drag him
into the up and I'm just going to snap
all these guys into place I don't
necessarily have to snap because we're
only covering rotation anyway but it's
just a habit that I've gotten into and
now I'm going to go ahead and translate
what is our what we're considering our
wrist so it's it's actually rotating but
we have another problem now we need it
to actually stay between the two exactly
as I mentioned earlier this constraint
only covers rotation exactly but the
cool thing is since we've already talked
about the position constraint we can now
take advantage of that
absolutely so now we can take a position
constraint drag it into the scene as
well and just like you saw earlier where
we can layer constraints we can use one
and the other we can use the position
constraint in here in tandem with our
three point constraint okay so let me
take my forearm piece and we'll make it
the constrained object we'll take our
elbow and drag it to source one when we
get a source two we'll go ahead and take
the wrist and set that as source two now
naturally what that's going to do is
make our constrained object our forearm
always stay directly in between these
two pieces mm-hmm so I'm going to snap
them into place so that nothing really
moves and then I'm going to take my
wrist piece and now when I translate it
look at that our forearm is now
following along so if you if you thought
of these as if they were motion capture
sensors we actually would have a forearm
that was moving properly from an elbow
right and now you can move the shoulder
box to reestablish your up vector what
that's going to do is basically roll
your arm very good makes sense okay all
right cool I think that's a very good
demonstration of using the three points
constraint along with the position
constraints all right all right so go
and delete those out and you everything
set back up and then we'll move on again
okay so delete these guys out just take
a second and kind of reorganize my scene
just a little bit
it looks pretty close to what I had
before good enough so what constraint
are we going to talk about now actually
right now we're gonna go over the I cake
and strain so so we have the ability to
actually apply I cages like we can
another 3d applications absolutely in
fact uh it's how can I put this it's a
lot like 3d applications but it's also
kind of not because in most 3d apps
you're applying AI kbase off its own
tool you know you go and you select an
IKE a tool and you actually place what
bone is going to go to from AO from
where and to where in MotionBuilder you
have the power to actually do that from
a constraint perspective okay so what
I'm going to do is kind of open up a
file here where I've already got a basic
arm kind of set up some things put
together real quickly over in Maya no
fancy skinning or nothing it's just a
cylinder and a few joints absolutely but
as you can see if we come in here and
open our seat up we'll go ahead and take
our choice NURBS a cylinder warp
cylinder one I didn't even rename the
joint one joint - yeah it was a very
quick thing as they can see by the
skinning year exactly but you can see I
mean everything is skinned we've got
some rotation we have a basic kind of an
arm joint if you will like maybe a bicep
and a forearm here so if we needed to
create our own rig or some sort of rig
that goes above and beyond what's
already supplied for you to be used with
a characterized character then you do
have AI kkpah bility absolutely so let's
go ahead and demonstrate that I'm going
to come back in here to my constraints
and I'm just going to drag an eye cake
constraint into the scene and look at
all the things we get over nd constraint
settings with lots of stuff and it looks
kind of daunting maybe a little
frightening at first but you know it's
really no big deal if you just kind of
sit back and read what they're asking
for so right now it's asking for the
first limb in our I K set up now
naturally that's going to come from the
root of our system okay in this case
like if this were an arm it would come
from the shoulder but you need the good
ol lock down in the scene Braille
absolutely because my settings area just
flashed over to the settings for the
joint so I'm going to go back in here to
my eye k double click it to bring it
settings up and I'm going to lock the
window again there we go now because
I've got a model that kind of covers up
my joints I'm going to be dragging my
joints over here from the scene browser
itself so I'll start off with joint one
and drag
into the first limb now the next cell is
open is the last limb note that I didn't
say the last joint that's actually the
key here if you can think of it as said
the last limb being the second to the
last joint the limb itself is the bone
so really there's no bone out here the
last limb would be right in here
therefore the the last that I'm sorry
the joint of the last limb would
actually be here okay
so I'm going to take joint number two
and drag it in as the last limb the
endpoint would be the final joint of the
scenario it's basically where your I
case solver is going to end so we'll go
ahead and open the expand this out we'll
take joint number three and drag it in
to the endpoint now we need an effector
we need something that we can move
around that will influence the location
of our I case solver so I'm going to
come in here to my elements and I'm just
going to take a null and drag it into
the scene and I'll drag it over this
joint so that it appears right there in
the same location of the joint just
because it's so hard to see will scale
him up so that he's real easy to make
out right there and we'll take him and
we will alt drag him with the left mouse
button into the effector slot now I have
a couple more things left that aren't
really necessary you can go ahead and
fire up the constraint right now and see
it work and actually later on when I'm
rigging up the helmet for our alien
character this is all I'm going to be
using but we have two more slots that
I'm going to go ahead and show you how
to use we have a hint and a floor let me
go ahead and take my my null here and
I'm gonna duplicate him just to get
another null of the same size quickly
and I'll just drag him pretty much right
up here directly above our little bone
system and let me alt drag him into the
hint cell and before I fire this up
we've also got a floor now our floor is
going to allow us to determine where
floor contact is now some of you have
already seen in MotionBuilder that you
can make your models respect the floor
you can take the route and pull them
down and their feet actually won't
penetrate past the floor area well with
this you're allowed to determine what's
going to be the level of the floor so
let me go ahead and make a plane so that
this will be a little more evident a
little easier to see and let me try that
again there we go it caught that time so
I'm going to go ahead and scale this up
kind of looks like a floor now and I'm
going to alt drag this plane into the
floor node and now everything's ready to
go I can go ahead and just activate this
it's going to say some objects are going
to move to accommodate that's okay go
ahead and you'll notice MotionBuilder
does a little bit of thinking now we can
take our effector which is the null we
have here and we can translate it just
like a just like I K now this isn't all
there already very familiar our effector
is just like the UN I K solver we can
move it around in our I can take a
handle like a handle thank you our goal
the bell depends on what application you
may be coming from absolutely but we
also have our hint now what our hint is
going to do is tell our I case solver in
which direction to bend exactly it's
also going to act as a pole vector if
you will for those who you guys coming
from Maya or it's going to act as a
target and those you guys come in from
other applications basically you can see
it's it's acting as a rotate plane as or
causing the eye case over that as they
rotate plane solver where basically
what's happening is we're controlling
the plane in which the eye case solution
is being generated on our elbow area is
going to always try to point towards
that target exactly and if that sounded
a little bit confusing I'll just kind of
try to elaborate on a little bit right
now if this hint were perfectly lined up
with our effector as you can see in our
axis down here in the corner we would be
bending Rik on a Y Z plane exactly so if
we were to move this our effector here
you'll notice that the whole eye case
system stays within that Y Z plane now
if we take our hint and we rotate it
around that plane that our eye K is
solving on actually rotates around just
to kind of clear up for those of you who
may not be familiar with rotate plane
solvers exactly now
well everybody from coming from other
applications of course should be
relatively familiar with targets and
it's basically the same thing on
controlling where it knees gonna point
or controlling where an elbows gonna
point exactly so that leaves us with one
more thing to show before we move on and
that's the floor the floor so you know
I've got this plane set up in here it is
designated as the floor so now I can
take my null that I've set up as my
vector and drag it through the floor
look at my I K itself
will not penetrate the floor it's
actually set up now to respect the floor
now once again I can take this the
effector and I can drag it as far down
past I want to and it'll stay there but
the ika itself won't go any further
right so you've got a constraint right
there okay very nice very well done all
right that pretty much shows off I K so
go ahead and right-click and delete that
out of the scene you know actually let
me just go ahead and start a new scene
entirely sounds good all right so
everything's pretty much back the way we
remember it let me go ahead and throw a
few cubes in there so everybody will
feel right at home and really we've only
got one more constraint left to show and
that's going to be the parent-child
constraint now this is one of the most
important constraints in animation
simply because any time that you're
animating something where a character
reaches down and picks up his glass of
water to take a drink you're going to be
using a parent child constraint to
actually make that glass of water go
with his hand okay so let me go ahead
and I'll just kind of rig up a quick
demonstration for you we put a few more
cubes in my scene I'm also I'm going to
be demonstrating this a little more
thoroughly when we start animating our
alien because we're gonna actually
animate him to where he picks up and
points his gun at somebody so let me get
another cube in here space him out to
right about here now let me go ahead and
I'll go under constraints and I'm gonna
drag a parent child constraint into the
scene I'll expand the the constraints
tab or a constraints folder inside my
scene browser Gus go ahead and open up
my scene so I can see all my cubes in
there as well now I'm going to go ahead
and start off just by setting up a
single parent-child relationship I'm
gonna take my uh my constrained object
that I've been using the one in the
middle the whole time so I'll continue
to have a little bit of continuity there
and alt drag him down into the
constrained object or the child cell the
source or the parent or once again I
need to lock turn that on settings area
this is very important everybody please
keep an eye on that so I'll double click
my source and drag it in and it becomes
the parent now let me just
go ahead and snap this as opposed to
activating it because this works a lot
like a positions constraint initially
and that if you just activate it your
child is going to excuse me it's going
to jump to the location of your parent
okay so let me go ahead and snap it to
begin with and you'll notice at first
it's going to behave like a perfect
combination between a rotation and a
position constraint you'll notice as I
move him positionally our child comes
with actually it works more just like a
regular parenting scenario exactly but I
mean there may be some people out there
who are familiar with parenting
scenarios as we think of them okay it's
possible you know we might have a
colleague in here be like I've never
seen a parent-child relation reason it
acts a little bit different than a
regular position rotations constraint as
a circle fact that the constrained
object cube is not just rotating in
place it's physically exactly as I was
about to go into that but you beat me to
it good work
so actually what we're doing is we're
taking our rotation data and our child
is rotating using the parent as its
pivot okay so I mean you can see that
most clearly as I rotate the
relationship like such absolutely and
once again you know I can translate them
and the child will come along but you
know this parent-child relationship is a
lot like a modern parent-child
relationship right basically wherever
you know like with real kids and adults
you and their parents their folks you
know you go to the grocery store and you
see the parents and they're walking
around the aisles and the little kids
are just following right along with them
but suddenly the kid might see something
and he'll just run off in the other
corner and the parent won't follow up
that's why you can go down to the local
parent store and buy yourself a lock I
could no absolutely yeah you really can
you can go ahead and you can lock this
so you can't move you're constrained
object at all but just something to keep
in mind in most parent-child
relationships you can move the child and
it will not influence the parent
basically is like a one-way street the
translation and rotation of the parent
affects the child but not the other way
around
so the as I drag my time slider across
the screen for just a quick
demonstration how you can move pains
this does allow you a couple of pretty
cool things as you know we took a little
bit of some Liberty earlier
the lesson with the three-point
constraint and had everybody imagining
that a series of cubes were actually
some various joints and perhaps a sensor
pattern so I'm gonna ask you guys to
kind of ride with me one more time and
we're gonna just kind of pretend some
more stuff let me go ahead I'll try to
make it a little bit easier on you let
me get my scale tool and let's say that
this is going to represent a hand I've
kind of flattened it out to the shape
maybe the palm of a hand I mean that'll
work just for this particular case and
then here I'm gonna have mmm I'll scale
them up a little bit we'll call this guy
like a table okay so we got a table
we've got a hand and here's our object
first I'm going to do is deactivate my
original constraint I'm going to take my
object and set it kind of roughly I'm
not going to get too pretty here a
scaling down will bit make them sit a
little better and I'm just going to set
him on top of my table now let's say I
have an animation where I want my hand
to come over and actually pick this
object up what I can do is make two
parent-child relationships one where the
object is parented to the table and
another where the object is parented to
the hand and I can animate the waiting
in between the two let me go ahead and
demonstrate that first thing I'm going
to do is take my my original constraint
which I have here where our cube our
original constrained object which you
can see here is constrained to our hand
object let me go ahead and drag another
parent-child relationship into the scene
and I'll take our table and alt drag him
into the parent I'll take our current
constrained object and drag it into the
child so now our child is actually
constrained to both of these nothing is
activated right now of course so nothing
has really moved so what I'm going to do
is come down here to where we are
constrained to the table and I'll snap
it into place and now we'll come over
here to my constraint that is actually
constraining our object to the hand and
I will snap it as well so nothing
actually moves so now if I were doing an
animation we've got our our object it's
sitting on a table we can now take our
hand and we can move it close to our
object let me out just just to be a
little picky of course I don't know
where I learned to be picky
no comment we'll just kind of move the
hand where it looks like it's about to
pick up the object and then at this
point we could take the waiting of our
second constraint and we could take it
down from 100 to zero and since it's a
parent-child relationship it's not going
to jump to the other guy and and now
when we move our hand away we just
picked up our object making interaction
with objects very simple you don't have
to worry about things
snapping exactly it actually you know
and we can kind of demonstrate this a
little bit I mean originally we brought
the hand over to the object we don't
necessarily have to do that I mean if we
had a character that could use something
that was kind of like some sort of
powers some sort of magical force like
you ours some magical he could stand
back from a distance and bactrim make
something up with his force like and
maybe conjure something that was like a
sword that had a laser for a blade he
could conjure that directly to his hand
like such exactly so as we steer clear
of copyright laws and give you just kind
of a brief example there to kind of get
your brains roll and as to the number of
ways you can use this constraint cuz
really the parent-child constraint is
something you're going to find yourself
using in any character animation where a
character interacts with objects exactly
so Zach I think that pretty much wraps
up all of the simple constraints that we
set out to talk about and absolutely I
think we've all we've gone over
everything really well pretty good
pretty well I'm thinking everybody
really can now get in there and use
these simple constraints and go over and
start experimenting with them alright
cool so from now what we need to do is
go ahead and move on and we're going to
start looking at relations and
expressions and then finally we'll start
getting into the character and do some
neat stuff with him so that's going to
wrap up and conclude this lesson right
here thanks everyone
all right