Part One: Rigging the Leg
Let’s
begin by rigging up the foot. We will need kinematics running from
the hip to the ankle and a reverse foot setup to give us proper
heel-to-toe rolling.
Since this kind
of foot setup is typical of most biped characters, a foot-control
digital asset has been created and made available for use with this
character.
1.
Set up a Top view
Tumble and zoom
around. End up focused on the feet.Turn
off the model’s display to let us focus.
2.
Add and Position a Foot control
Press tab
> foot control. RMB-click
to put it at the origin. Press tab
> Transform.
3.
Edit the Position of the Nulls
Go to the Setup
tab and turn on make nulls editable.
This will make the nulls selectable on an individual basis
Snap nulls to
bones.
Scale up foot
icon. Toggle off "editable" flag.
Here we get
a foot control asset and place it into the workspace.
It gets moved
into place and the first thing we notice is that the control nulls
are not located where they are needed.
Controls have been added to allow for these points to be customized
for any foot which allows this setup asset to work with any biped
character. In only a few steps the nulls are aligned with this character.
3.
Add Kinematics
Go to the kinematics
panel. Click add kinematics.
Next we will
hook up the kinematics for the leg and foot using a button that
runs a series of hscript commands to hook up the null objects of
the foot control to the leg bones.
Notice how when the button is pressed, the various bones are referenced.
Digital assets can contain scripts for simplifying tasks that would
otherwise require a lot of clicks.
Now lets test this.
4.
Test the setup
Access the pose
tool. Click on the foot control and manipulate it. Undo.
When we pick the control with the pose tool a handle and various
HUD sliders appear.
These are the animator’s controls.
As you can see the foot controls built in interface along with the
quick rigging and kinematic setup make it easy to get a foot roll
with Houdini.\
You can even mirror the whole left leg along with the control object
to get a new leg with the foot_control already setup.
Very quickly you can see the power of using digital assets as a
rigging tool for setting up characters quickly with easy to use
handles.
A similar technique would be used to rig up other parts of the character.
4.
Mirror the arms and legs
5.
Create the character asset
Zoom out in
network to see all the parts.
Select them and collpase into subnet.
Drag the foot control to type manager panel. Show parameters.
Characters themselvs are best set up as digital assets.
This involves taking all the bones, geometry and shaders and collapsing
them into a subnet.
This can then be turned into an operator type with its own controls.
To help build up its interface, we can simply drag nodes such as
the foot control node into the properties panel and the parameters
are published. From here the character’s interface is built.
Let’s jump to a version of this character that is all rigged
up.
Part
Two: Posing a Digital Asset Character
Install the OPsiggraph.otl library.
1.
Load the Character
Press tab >
Beatrice. RMB click to accept and place girl.
Zoom and Tumble
to view character.
Show parameter
pane. Play with the display options under appearance. Turn off the
"other bones."
2.
Position the Character
3.
Pose the Character
Get the Pose
tool. Click on the feet. The whole character is selected.
Turn off selectability of digital asset node and turn off "select
entire subnet."
Click on feet. Now the foot controls appear with rolling sliders
and main handle. Pose the foot.
Pose the other foot and the pelvis control.
Pose the hands. (handles) (there are not any finger or facial controls)
Pose the spine (bones)
4.
Add a Second Beatrice
5.
Update the Digital Asset
Install the
Opsiggraph_new.otl library.
Select the new defintion.
Update Beatrice.
6.
Set the Display options
7.
Continue Posing the Characters
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