In this lesson, using
automatically created motion as the basis, you’ll animate a biped
walking with a rolling, springy step.
The automatic footsteps
generate a starting point for you. You’ll then change the automatic
walk into something more expressive and distinctive. This sophisticated
yet simple approach results in a natural-looking motion that you
can create quickly.
Set up the lesson:
- Reset 3ds Max.
- On the Quick Access toolbar, click (Open File), navigate to
the \character_animation\footstep_animation folder,
and open walk_start.max.
NoteIf a dialog asks
whether you want to use the scene’s Gamma And LUT settings, accept
the scene Gamma settings, and click OK. If a dialog asks whether
to use the scene’s units, accept the scene units, and click OK.
In this file, a biped is standing near the origin.
- Switch to Local coordinates, if they
are not already active.
- Maximize the Perspective viewport by
pressing Alt+W.
- Click any part of the biped to select
it.
A white box outlines
the selected body part.
- Go to the Motion panel.
The Biped controls are displayed.
Next you’ll turn on Footstep Mode. If Figure
Mode was on, it turns off automatically.
Create multiple footsteps:
- On the Motion panel Biped rollout, turn
on (Footstep Mode).
- On the Footstep Creation rollout, click (Create Multiple Footsteps).
- In the Create Multiple Footsteps: Walk
dialog General
group, change Number Of Footsteps to 8, then click
OK.
Footprints are displayed
in white in the viewport. These are inactive footsteps. They do
not yet control any animation for the biped. If you click the Play
Animation button, the biped won't move.
- In the Footstep Operations rollout, click (Create Keys For Inactive
Footsteps).
The footsteps are activated.
Animation keys are created for the biped.
- Play the animation.
The biped walks.
- On the Biped rollout, turn off the Footstep
Mode button.
Notice that the first
footstep is numbered 0, and the last footstep is numbered 7.
- In the Track Selection Rollout, click (Body Horizontal), if is
not already turned on. This selects the horizontal position track for
the center of mass (COM) object.
The track bar displays keys for the length of
the animation.
- Play the animation.
The biped walks, but without much character.
In the following procedures, you'll begin individualizing
the motion by adjusting the keys for the Body Horizontal, Vertical,
and Rotation tracks. You'll exaggerate the rotation of the center
of mass to create a more energetic walk.
Adjust body rotation keys:
- In the Perspective viewport, click (the front face of the ViewCube)
to shift the view so that the biped is walking toward you. Then
drag the time slider to frame 0.
Be sure that a part of the biped is still selected.
In the Track Selection rollout, click (Body Rotation).
- Right-click the track bar, and from the
pop-up menu choose Filter Current
Transform.
Now the track bar displays
the rotation keys.
- On the 3ds Max status bar, click (Key Mode Toggle) button
to turn it on.
Key mode lets you use
Previous and Next Key buttons to jump between keyframes for the
selected object. You can also use the < and > keys on the keyboard to move
between keyframes without clicking the mouse.
- Press > on
the keyboard to advance the time slider to frame 24.
- Use the Transform gizmo to adjust the
body rotation. Move your cursor over the gizmo; when the circle
turns yellow and the X in the center turns red, click and drag to
rotate. If you can't see the X, zoom into the viewport. Rotate 5 to 10 degrees
about the X axis to move the hips down toward the leg that is in
motion. When you rotate, one foot will cross the other.
TipThe rotation is displayed
in yellow text above the Transform gizmo, and also in the Coordinate
fields on the status bar. You can use the plus (+) and minus (–)
keys to change the size of the Transform gizmo.
- On the Motion panel Key Info rollout, click (Set Key).
When you set the key, the biped will shift position
slightly. In the viewport, you can see that the blue foot is no
longer crossing the green.
What is happening is that the foot, calf, and
thigh bones are being controlled by the footstep gizmos. The footsteps
represent a pair of keys with IK Blend set to 1 and the Join To
Prev IK key turned on. When you set the key, these settings force
the foot, calf, and leg bones back into the correct path for walking.
- Click Next Key three times to move to
frame 40.
- Rotate the Transform gizmo –6 to –10 degrees
about the X axis.
- Slowly go through the rest of the rotation
keys, repeating this process. At keys where the blue foot comes
in contact with the ground (frames 40, 69, and 99), rotate about
the X axis in a negative direction, then set a key. At keys where
the green foot is down (frames 54, 84, 116), rotate about the X
axis in a positive direction, then set a key.
- Repeat this pattern until you have finished
rotating the COM at the end of the animation. Don't make your adjustments
too precise. Slight variations from frame to frame make the motion
look more natural.
When you are done, play
the animation and notice the increased hip swings that result from
rotating the center of mass back and forth.
- On the Biped rollout, click (Save File) and save the file
as mywalk.bip.
If you load the newly saved mywalk.bip file
into a scene containing a skinned character, the character will
swing its hips according to the instructions you saved in this file.
Play the animation to determine if you need to adjust it. For instance,
Dr. X (from the quick start tutorial) has huge feet, which may need
to be moved further apart so they don't pass through the legs accidentally.
Add spring to the step:
- Continue from before, or load the mywalk.bip file that you saved
earlier.
To load a BIP file, create
or select a biped. On the Motion panel Biped rollout, click (Load File), and open the
file. This transfers all the movement information in the file to
the biped.
- On the Track Selection rollout, click (Body Vertical).
This selects the vertical position track for
the center of mass object.
- Turn on (Key Mode Toggle), if it
isn't already on.
- Starting at frame 0, move through the
animation using the < and > keys. When you come to a frame
where either a green or blue foot comes in contact with the ground,
move the COM down just a few units.
The knees bend because the feet are controlled
by the footsteps.
- After making a change at a frame, click (Set Key) on the Key Info
rollout.
This sets a key for the
change you've made in the viewport; otherwise, the change is discarded.
- Play the animation.
The biped walks with newfound bounce.
- On the Biped rollout, click (Save File). Name the file mywalk2.bip.
Add arm and hand motions:
Arm and hand motions
are an integral part of an individual’s gait. In the following sequence,
you'll customize the arm motion by moving the hands and rotating
the arms.
You previously created
keyframes using the Set Key button; however, for this technique,
you'll use Auto Key instead.
- Continue from before, or load mywalk2.bip, the file you saved
in the previous section.
If you prefer, you can
begin at the end of the last procedure by opening springystep.max.
- Turn on (Auto Key).
- Drag the time slider to frame 0.
- Dragging the time slider to the right,
flip through the frames of animation. Drag forward and backward,
and watch the how the arms and legs swing. Study the motion carefully.
When the green foot is extended, the blue arm
swings forward. When the blue foot swings out, the green arm swings
forward. See if you can find the frame at which the hand extends
the farthest forward.
- In the viewport, select the green hand
of the biped (Bip01 RHand).
The track bar displays the keys for the hand.
- Drag the time slider to frame 30.
There is a key in track bar at that frame for
the hand object.
- Right-click the hand, and choose Move
from the quad menu.
Using the Transform gizmo,
move the hand approximately 10 units upward
on the Z axis.
By moving the hand, you've also rotated the
two arm bones. The keys for the hand and arm bones are stored on
a single track.
- Select the Bip01 R UpperArm object, then
right-click and choose Rotate. Rotate the upper arm approximately –30 degrees
about the Z axis.
- Rotate the upper arm approximately 20 degrees
about the Y axis, so the elbows are flying out and away from the
body.
- Select the forearm object (Bip01
R Forearm) and rotate it so the hand moves closer to
the chest.
You can position the arm using forward kinematics
(the rotation of the parent objects) or inverse kinematics, using
position transform on the end of the chain: in this case, the position
of the wrist. You can also rotate the hands.
- Use (Orbit) to adjust the view
angle so you can see the angle of the other arm behind the biped.
- Select the blue hand, and right-click
to choose Move. Move the hand further away from the biped's body.
Then move the blue hand upward on the Z axis so the elbow bends
slightly.
- Scrub the time slider back and forth
to observe the animation so far.
- Repeat the process at frames 60 and 90.
- Repeat for the other side at frames 45
and 75.
TipIf you want exact duplication of these arm
positions, you can use the tools in the Copy/Paste rollout. Select
both arm assemblies, create a collection, then use Copy Posture
and Paste Opposite at the correct frames. See
Creating a Simple Freeform Animation for
information on using those features.
- Play the animation.
Save it as mywalk3.bip.
- To see your work on a skinned character, open dr_x_03.max from the folder \character_animation\quick_start\ folder,
and then load your mywalk3.bip file.
For comparison, you can also load distinctive_walk_final.bip from the
folder \sceneassets\animations\.
Remember to select part of the biped to access the Biped rollout.
Add head motions:
You can edit the head
motion to make the biped’s walk look more natural. In this procedure,
you'll add head rotations to accentuate the COM rotation.
- Turn on (Auto Key), if it isn’t
on already.
- Turn on (Key Mode Toggle), if it
isn’t on already.
- Drag the time slider to frame 0.
- In the Perspective viewport, select the
biped's head using (Select And Rotate).
- Rotate the head down as if the biped
is asleep.
- Advance the time slider to the next keyframe
by pressing the > key.
- Keyframe rotations for the head. You
can rotate the head to counterbalance the angle of the shoulders.
Or, you can rotate the head in the opposite direction so it follows
the rotation of the COM. Each rotation will give a different result.
Extreme rotations should be avoided. Also, be careful to put the
rotations only on existing keys.
- Continue to jump through the head's keys,
setting rotations of your choice to animate the head.
Natural head motion is smooth, so the orientations
should change gradually from one key to the next.
- Turn off (Auto Key) and (Key Mode Toggle).
- Play the animation, and notice how much
the biped’s head movements add to the animation.
You can now save your work as mywalk4.bip.
You can check your file against head_rotate_with.bip and head_rotate_against.bip. Both these
BIP files are in the folder \sceneassets\animations\.
To see a finished version
of the walk, you can go to \scenes\character_animation\footstep_animation and
open distinctive_walk.max.