Hi everybody!
This is Mathias Möhl for mamoworld.com and in this tutorial I want to create
an automatic walk cycle for this character that has been rigged here in After Effects
with the script Limber.
So like DuiK tools or Rubber Hose, Limber can create Inverse Kinematics (or IK)
for legs and arms, such that when I move this foot, for example, the entire leg moves accordingly.
In this tutorial I assume that you already created such a character rig with Limber and
want to focus on the next step, namely to apply the Automatic Walk Cycle
of our extension iExpressions to the character.
Because with this automatic walk cycle, you can simply keyframe the position of the character
and the expression moves the legs and arm accordingly to create a walk cycle.
The iExpressions walk cycle works with any character
no matter whether it is created with Limber, DuiK, Rubber Hose or whatever.
The only requirement is that your character is rigged such that you have
one controller on each hand and each foot,
one controller that moves the entire body without the hands and feet
and one master controller that moves the entire character including the hands and feet
or in other words including all those other controllers.
Then you just move this master controller and the expression moves all other controllers
for you.
Limber creates arms and legs with one controller on each end
so for each arm we have one controller at the wrist
and one at the shoulder and for each leg we have one controller at the ankle
and one at the hip.
So the controllers at the ankles and the wrists are already what we need for the walk cycle,
but the controller for the body and the master controller are still missing.
So let’s create a new solid for the body controller (you can of course also use nulls
or any other layer) and place it here on the body.
Now let’s parent everything to it that belongs to the body.
The shoulder controllers of our character are already parented to the shirt
and the shirt is parented to the dungaree.
The dungaree has no parent, yet, so we parent it to our body controller.
When we now move the controller, the upper part of the body moves with it,
but the legs and the head are not yet attached to it.
Hence, we also parent the neck and the the two hip controllers to it.
How exactly the parenting structure is depends on your character, it is only important that
in the end you have one layer with which you can move the character’s body as I do here.
So everything moves with it, except the hands and feet.
Now let’s disable the visibility of the shoulder and hip controllers,
since those are now moved by our body controller.
So the five controllers we can see now are the ones that will be animated by the walk
cycle iExpression and now the only thing that is missing is our master controller that moves
the entire character including all those other controllers.
So we create again a new solid, and parent the five controllers for the body, arms and
legs to it.
Now this master controller moves the entire character and in contrast to the body controller
it also moves the hands and feet.
Now it is time to open iExpressions and in the library in the physics bundle open the
walk cycle iExpression.
In the expression, we now need to enter the names of all our controllers.
So the left foot is controlled by this layer, so we copy and paste its name.
Then we do the same for the right foot, the left hand, right hand and the body controller.
Instead of the names, you could also enter the layer indices, but then when you add new
layers in the composition, these indices will change and the expression won’t notice this,
so in general I recommend to use the layer names.
Finally, the iExpression also needs a ground layer.
This is necessary because instead of moving the character, you can also move the ground.
So as ground you can use any layer that is part of your background, or also a null layer.
I have prepared here a simple layer with name “background”, so let’s enter the name
“background” here.
We keep the walking style and direction at the default and are now almost ready to apply
the expression.
Before we apply it, we place all our controllers such that the character is in a more or less
neutral pose.
Normally, neutral would mean that arms and legs point straight downwards but since our
zombie has a pretty ducked posture, we keep a bit of that in our neutral pose.
Now we select the 5 controller that the expression should animate for us - so all these controllers,
except for the master controller - and apply the iExpression.
If we now keyframe the master controller, the character starts walking, but it makes
huge steps as you can see from the movement of the controllers.
Again, this depends on your character, but you can control this using the scale parameters
of the expression.
We make the steps half as big by setting the scale of the Foot and Hand Movement and the
body to 50%.
This already looks much better!
To make the movement more appropriate for a zombie, he should raise his feet less than
an average character, so we lower the y-movement of the feet even more to 25%.
Also, we increate the body movement again to 100% such that the body moves up and down
a lot during walking to give it a bit more weight.
So that’s how easy you an adjust the walk cycle to your character.
Now, instead of moving the character itself using the master controller, we can also move
our background layer.
Last but not least I want to mention that even though the controllers are now all driven
by the iExpression, you can still keyframe them manually on top of the walk cycle.
So a few frames before the character stops we can, for example, set a keyframe to ensure
that up to that point everything stays as it is and then at the point where it really
stops, we refine its pose however we want with additional keyframes . Now, as you can
see the character walks and then stops in the pose that we keyframed manually.
That’s the end of this tutorial.
I hope you enjoyed it.
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See you next time!