Now,
let's go to the second attribute.
The inherit swivel. This is actually
just a fake. Whai I did was create
a script controller that controls
the FootControl's Z rotation based
on the value of this slider. If
the slider is at 1, the FootControl
(and thus the whole foot) will rotate
with the leg. If its value is 0,
it won't rotate. It's really simple
to set up, so let's start doing
it.
Select
the FootControl point object, and
assing a script controller to its
Y rotation track. The script controller
window will appear. There will be
a number on it. TAKE NOTE OF THAT
NUMBER! You may insert a line or
two before it. Then, enter the following
script...
First,
select the two IK chains in the
foot, and turn off the Use swivel
angle at the IK solver properties
rollout (motion panel). We don't
need swivel angles for these solvers.
Now, select the ControlFoot object,
and add the following custom attributes
to it...
Notice
that the actual names of the nodes
involved don't match mines. Remember
I add a LT or RT suffix to each
node depending on what part of the
character it is (RT= right, LT=left),
and that I add a prefix depending
on the character so that I won't
have duplicate names when merging
characters together (A_ = Astro).
Just adjust the names as needed,
but these MUST match the ones of
your objects, or you'll get undefined
errors when evaluating the script.
Substitute the number I've got at
the end of the script (-1.57074)
with the one the script controller
window gave you when it opened (it
can be a positive or negative number).
Press evaluate. If you don't get
any errors, adjust the swivel angle.
You'll notice that the knee rotates,
but the foot doesn't. This is because
there seems to be an issue with
script controllers referrencing
attributes located in the same object
they're in. To have the controller
update itself, move the slderbar
a bit. You'll see the foot react.
If it rotates in the opposite direction,
erase the minus sign before the
degtorad expression in the script.
Close the window. Now, convert this
script controller into a list controller
(the scrip controller will be inside
of it), assign a bezier floar controller
to the available track and set it
as active.
There
is another node that needs to react
to the inherit swivel, adn it's
the Rotator_foot object. Now, this
one is a little bit tricky, because
it's not aligned to the leg. However
this doesn't mean it won't work.
Here's how it's done.
Select
the rotation track on this object
(I used a local euler controller).
Convert it onto a list controller.
Assign another euler controller
at the avalialble track. Name this
controller something like EulerXYZ_auto.
Now, assign script controllers to
both the X and Y tracks. Enter the
exact same script you have above
to these controllers. The difference
will be that you won't need to add
or substract a number from the expression,
since the controller gave you a
value of 0 when it was assigned.
The only difference between both
tracks is that you should enter
a number at the end of the expression
for the X track. This is the script
I have:
So,
how did I get that 1.7? By eyeballing.
What does it do? It compensates
for the misaalignement between the
leg's oriantation and the foot's.
If you don't add that number, you'll
see the Rotator over-rotate in response
to the swivel angle. This division
compensates and makes the Rotator
rotate properly. By the way, for
some strange reason, this object
won't react interactively. Just
scrub the time slider to force an
update.
There
you are. You've got everything all
wired up now. We need still to add
some more controls so that our foot
behaves solidly as one single unit,
so let's take that last stretch.
Select
the LocalRotation node, and assign
an expression controller to its
X rotation track. Take note of the
number that appears at the expression
window. Create a scalar variable,
and assign it to the Rotator_foot's
X rotation track. In the expression
window, enter the variable's name
and add or subbstract the number
the expression gave you from it.
Close the window. Turn this expression
controller into a list controller,
assign a bezier controller to the
available track, and set it as active.
So,
we're done. Your foot (and at this
point, the whole puppet) must be
ready and steady. I always try my
rigs by doing a small short animation
where the rig is really stressed.
If your rig breaks, you need to
work on it. If it does the job,
you're ready to go into production.
But before you jump into doing Toy
Story 3, let's do the last touch
ups to the rig.
ANIMATABLE PIVOT POINTS
What
we'll do is add some link constraints
to the puppet, so we can controll
it much better. I'm not even going
to explain the procedure, but here's
what I did and why.
So,
what is this all about? Obviously,
you'll want to keep the hands and
feet independent from the body when
animating, so why link them to it?
First, it allows me to place my
character with more ease. When you
merge a character onto a new scene,
most of the time you'll need to
move him. This way, I just move
the COM, and the hands and feet
go with it. When I start animating,
I just add another object as a new
target (most of the times I add
the floor), and animate. Also, it
works when the character needs to
fly. By having the hands and legs
linked to the COM, I can concentrate
of the flying without worrying of
having nodes stay behind. And the
third advantage is that if my character
needs to yield, say, a daito (a
sword you hold with both hands),
I can link both hands to it and
animate the sword, instead of linking
the sword to one hand, animating
the hand, and having to match the
other hand to the sword (this also
applies to carrying a box).
3DTotal
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And
what about the COM? Well, by linking
it to two different objects (the
two Points we added) at different
times, you can have an animatable
pivot point. What if you want the
character to do a backflip, land
on one finger, and rotate several
times on it while twisiting a-la
break dance? Easy. When you're done
with the backflip, just place the
pivot at the point of his finger
as he lands, link the COM to it,
and animate the pivot rotating.
The whole character will rotate
at that point (I also use the ground
as a target for the constraint when
I need no extra pivot). I don't
add the pivots and the pivot constraint
until my character is already on
stage, so you might want to skip
that on your character files, and
leave it for the scene files.
I
hope you enjoyed creating this rig.
As you can see, character rigging
is an art onto itself, and I must
say I enjoy rigging characters as
much as I enjoy animating them.
I've uploaded my rig file, so you
can take a look at it, disect it,
modify it, etc. I hope this was
of any help, and that you'll be
able to rig anything else you come
up with. Have fun, and let me know
how you liked this. Luck!!
So,
how did I get that 1.7? By eyeballing.
What does it do? It compensates
for the misaalignement between the
leg's oriantation and the foot's.
If you don't add that number, you'll
see the Rotator over-rotate in response
to the swivel angle. This division
compensates and makes the Rotator
rotate properly. By the way, for
some strange reason, this object
won't react interactively. Just
scrub the time slider to force an
update.
