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FACTFILE
FOR
Blender
DIFFICULTY
Intermediate / Advanced
TIME TAKEN
One day
ON THE CD
Full-size screenshots
Blend file for Proog
Textures
Blend files for stages
2,15, 21 and 26
ALSO REQUIRED
More supporting files can
be found on our website
Turn a simple walk cycle into a stroll with style! Improve your character animation in our Blender masterclass,
which makes use of genuine rigs from the movie Elephants Dream, provided on the CD BY BASSAM KURDALI
successsteps toW
alk cycles are one of the staples
of 3D character animation. Yet its
all too easy to end up with bland,
robotic movements. In this tutorial,
you will learn how to create a walk with personality,
keyframing and refining a basic movement cycle, then
layering secondary animations over the top.
For this, we will use Blenders NLA Editor (Nonlinear
Animation Editor). It works just like a video editor, but using
animation strips instead of video clips. Each strip representsinstances of an action that can be moved, scaled in time or
layered on top of other strips. This allows you to create an
action that contains one walking cycle, while the strip itself
contains as many cycles as are required for your character to
walk along the path you have assigned to it. The repetitive
nature of the cycling can be offset by using additive action
strips to alter the motion, or by adding other strips to layer
different actions on top of the walk.
In the tutorial, well be using Proog, the lead character in
the worlds first open source animated film, Elephants Dream.
First, well keyframe a basic walk cycle and make the action
loop properly, then put him on a path and add some actions and
layer animations on top of his walk. Finally, well look at some
of the extra cloth animation controls the character rig contains.
Dont worry too much about Proogs coat until the very last step
of the tutorial to look good, it needs some hand tweaking.
The walkthrough is intended for readers who already have
some familiarity with both Blenderand the basic concepts
of animating a walk cycle. If you get stuck, refer to the
annotated screenshots on the CD. The disc also contains a set
of numbered scene files that will enable you to pick up the
tutorial again at the corresponding steps, and more are availablefor download from www.3dworldmag.com/stoppress .
The Proog model itself is the genuine rigged character
from the movie, and is available under a Creative Commons
attribution licence, so it can be used for any project you like.
Most of the tutorial can be completed in Blender 2.41,
which is included on the disc. However, some of the advanced
steps require Blender 2.42, which should be a free public
download from www.blender.org by the time you read this.
Bassam Kurdali is a freelance animator. He recently finished
work as Director/Animation Director on Elephants Dream
www.freefactory.org
BLENDERBLENDER
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ON THE WEBBonus scene files andfinished walk animationwww.3dworldmag.com
ON THE CDBlender 2.41 (seenote in introductionabout version 2.42)
SEE PAGE 82
Animating better walk cycles | TUTORIALS
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STAGE ONE |Creating a sneaky-looking walk cycle
Launch Blenderand adjust the panels until you have
Action, NLA and IPO Curve Editors, a 3D Viewport,
buttons and timeline windows onscreen. Split and
join panels by hovering the mouse over their edges and
right-clicking. Move the edges by clicking and dragging. Drag
down the top menu bar, select Edit Methods and, under Auto
keyframe, select Available, drag the bar up and hit [Ctrl]+[U].
01Load Proog: choose File > Open or [F1] and browse
to where you extracted the files from the CD. Select
stage_2.blend and hit [Enter]. If you want to keep
you current layout, deselect Load UI at the bottom of the file
selection window, otherwise you will get the same UI layout
saved with the file. Note: the full-size screenshots are on the
CD, so dont worry about reading the tiny annotations above!
02
Pose the torso in the same way as you posed the foot
in Step 3: select control bones, rotate and/or move
them until you like the contact pose. The cage-likebodybase control can be used to move and rotate the entire
torso; the rest of the spine (body, back, neck and head) can
be rotated independently (body can also be translated, but
well just rotate it). If you rotate, key Rot; if you move, key Loc.
05
Pose the arms and shoulders by rotating and keying
rotations so that the right arm is forward and the
left is backward. Rotate the palm, thumb and finger
bones. The fingers and thumbs are each controlled by one
bone: rotating it rotates the finger, scaling causes the finger
to curl. Key each digits rotation and scale. ([Shift]-select
multiple bones and key them together to save time).
06
EXPERT TIPSetting up contact pointsWell create the walk cycle in one
place using pose-to-pose techniques.
Imagine that youre animating a
character walking on a treadmill,
with each planted foot rolling back,
when planning the poses. You can
plan the cycle between any of the
key poses, but the simplest way is to
start from the contact positionswhere the front foot just begins to
touch the ground, then do the
passing position (where the back
foot passes the front). Finally, do the
down position and the up position.
These last two give a sense of
gravity and force to the walk cycle.
i
For the first contact position, drag the Frame Marker
to frame one, then go to the Side View in the 3D
Viewport. Select and move Proogs left foot half astep forward and a touch inwards. Dont lift it on the Z-Axis!
Rotate it so his toes are pointing up and turned out. (Pronate
by rotating on the Y-Axis.) Press the [I] key and select LocRot
to set a keyframe.
03Heres a little trick: select the left foot, press the
down arrow on the 3D Viewport header (Copy Pose),
then the small upwards icon with the pink arrow(Paste Mirrored Pose). The right foot is now in the mirrored
position of the left foot, so move the right foot backwards,
zero its X and Y rotation, then key it with the [I] key.
04
EXPERT TIPUsing manipulatorsUse manipulators for positioning,
rotating and scaling. These can be
turned on and off with the hand iconin the 3D Viewport, and the buttons
to choose translate, scale or rotate
can be [Shift]-clicked to select more
than one at a time. The drop-down
menu with the options Global,
Local, Normal and View selects the
alignment of the manipulator axis.
Generally, Normal is the most useful
for posing bones, since it aligns with
the axis of each bone. You can also
use hotkeys to constrain motion in
the 3D Viewport by pressing the axis
letter after initiating a transform.
i EXPERT TIPThe layers providedProogs armature has 16 visibility
layers that help minimise the clutter
in the 3D Viewport, Action Editor andNLA Editor. The first layer contains
his body and leg bones; the second
has his left arm FK controls; the
third, his left arm IK controls; and the
the fourth, his left palm and finger
controls. The fifth, sixth and seventh
layers control his right arm and hand
in the same way. The stride bone is
on layer eight, and the facial controls
are on layer nine. Layer 11 has cloth
fix-up controls. Other layers contain
bones that you shouldnt animate
and are supposed to be hidden.
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Go to frame 5 (or the first down position in the
action). In the 3D Viewport, select the stride bone
and press the [I] key and select Loc to key its
location. Click on Stride Root in the Armature Bones panel.
Move the bone L_stride until it lines up with the back of
the left heel in the side view. L_stride is just a marker, so
it doesnt matter if its keyed.
13Go to the last frame in which the left foot is in
contact with the ground (in my case, frame 34
this may differ depending on the tweaks you
applied in Step 12). Move the stride bone in the Y-Axis until
the L_stride triangle is aligned with the back of the left heel.
Dont move or key L_stride itself; just the stride bone.
14
Thats the first pose done! Save time by pressing the
VCR-style record button in the timeline; this turns
on Auto-Keying. Select all the bones posed so far
and select the Copy Pose arrow in the header. Then move the
frame counter 24 frames forward, and hit the Paste Mirrored
Pose arrow; another 24, and hit the Paste Pose arrow. You
now have the character skating between contact positions.
07Now the passing position (frame 16). This is where
the back foot passes the front foot in the middle
of the cycle. Lift the right foot up and make sure to
remove the X and Y rotation on the left foot, but dont move
its location. Pose the hips and other body parts as shown
above, and then select all the bones that are keyed here.
Copy the pose, go to frame 40 and Paste Mirrored Pose.
09
STAGE TWO |Making Proog walk along a path
Select the left foot and go into the IPO Curve Editor
window (make sure its set to show Pose IPOs), then
click on the label LocY. Select the Y location curve
and hit [Tab] in the IPO Curve Editor, then select the Bezier
handles between frames 1 and 24 and press [V] to make
that section straight. Do the same for the right foot between
frames 24 and 48.
08
EXPERT TIPHow this method worksWhile posing Proog to create the
walk cycle, think of the stride bone
(see Step 13) as a conveyor belt
moving backwards that the character
walks on. When applying the stride
to a path, Blendercycles the action
and uses the stride bone to control
the speed of the cycles.
The stride bone itself remains
stationary on the path for every
cycle of the action. This makes the
character move steadily forwards
along the path. You need to key the
first and last frame of the action on
the stride bone itself for this to
work correctly.
i
Next, create the up position of the foot: the highest
one after the passing position. Try to create a sense
of Proog pushing his weight up and forward whileon his resting leg. Again, Copy Pose and Paste Mirrored Pose
to get the mirror of the pose done. Now delete all the extra
location keys within straight segments of the feet IPO curves.
11We can continue to break down the walk into poses,
or do straight ahead runs on the feet, head, arms, and
neglected body parts such as fingers. Break apartthe motions of joints (try to get the hands and fingers to trail
the arms, and so on) to limber the motion up. Tinker with the
Action Editor and 3D Viewport until the movement looks good.
12The first down position is frame 5. Clear X and Y
rotation of the left foot and rotation of the ankle
and toe, select them and press [I] > Available. GetProogs weight over his front foot and swing the arms further
than in the contact pose. Paste Mirrored Pose on frame 29.
Straighten the foot curves between down and contact poses.
10
STAGE ONE (Continued) |Creating a sneaky-looking walk cycle
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Select the stride bone and, in the IPO Curve Editor,
select its Y Location curve. In the header menu,
select Curve > Extend Mode > Extrapolation. The
curve becomes a straight line. Go to frame one, put the mouse
in the IPO Curve Editor window and press [I] to insert a key.
Do the same at frame 49 (the last frame of the action). In the
Action Editor, delete the original stride bone keys at 5 and 34.
15
In the 3D Viewport, press [Ctrl]+[Tab] to take the
armature out of Pose Mode, select the path, then
[Shift]-select the armature and hit [Ctrl]+[Alt]+[C]
and add a Follow Path constraint to the armature. In the Panels
window, select the Object buttons, go to the Constraints
panel, and make sure the CurveFollow button is pressed the
follow (Fw) direction is in -Y, and Z is the Up vector.
20
Tweak the speed of the movement by clicking on
the path and going to an IPO Curve Editor, then
editing the speed curve as shown above. Change
the Strip End time to the end of the animation, and adjust the
end frame of the animation. And thats it! Youve got Proog
walking!
21
STAGE TWO (Continued) |Making Proog walk along a path
Check that the right foot matches up with the stride:
simply use the R_stride marker and line it up with
the back of the right heel in any frame in which
the right foot is in contact with the ground. The R_stride
should remain aligned in all other ground-contacting frames,
otherwise the right foot needs to be adjusted.
16
Select proogskel. If you havent named the
action, do so now. Delete the link to the action by
clicking the x next to its name in the Action Editor.Mouseover the NLA Editor and add ([Shift]+[A]) the action as
a strip (or mouseover the NLA window and press [Alt]+[C] to
convert the action to an action strip). Make sure that youre in
NLA Mode (see the Expert Tips box after Step 21).
18In the NLA Editor, hit [N] to get the strips Transform
Properties window, if it isnt already visible. Check
the Stride Path option, and make sure the StrideBone option has the stride bone name, and that the axis
for the striding is the Y-Axis.
19To create the path on which Proog will walk, hit
[Spacebar] while in the 3D Viewport. Select Add >
Curve > Path. Press [Tab] once to go to Object Mode,then press [Alt]+[G] followed by [Alt]+[R] to clear its location
and rotation. Press [Tab] again to go into Edit Mode and edit
the path until you achieve something you like the look of.
Dont make it too extreme or the walk cycle will break.
17
EXPERT TIPSwitching between modesWhen adding new objects, Blender
automatically enters Edit Mode on
that object. This allows you to edit
vertices/bones in sub-object level.
Blenders working modes are
accessible via the pop-up menu in the
3D Viewport header, or via hotkeys.
They consist of, in order: Object
Mode, Pose Mode (armatures mustbe in Pose Mode before they can be
animated), Edit Mode, and modes for
weight and face painting on meshes.
To toggle Edit Mode on and off, use
[Tab], and to toggle Pose Mode
(this is only available for armatures),
use [Ctrl]+[Tab].
i
EXPERT TIPSingle actions vs stripsTo display a single action rather than
a strip, click on the button in the
NLA Editor next to the name of thearmature. When the button shows
the Action Editor icon, the armature
displays only the results of that
actions keys. When it shows the NLA
Editor icon, the armature displays the
results of NLA strip animations. For
path-based animation to take place,
you must be in NLA Mode or the
armature will only display the result
of one motion cycle. If youre editing a
single action, you can use the toggle
to capture the NLA-based state at any
frame and key it in your action.
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Before starting to create the action, select and key
the bones you intend to animate (the head, neck,
back, shoulders and arm bones, including the hands)
at the last and first frame of the action. This allows you to
blend the action from the current animation without having
to use the Blendin/Blendout feature.
24
To finish off, refine the cloth animation. Select all
the strips in the NLA Editor by pressing the [A]
key once or twice. Move them roughly 30 frames
in and dont forget to edit the speed curve of the path as
before. Now, bake the cloth simulation by clicking on the
ProogSoftProx object on layer 15, and in the Physics buttons,
bake the simulation over the range of the animation. The
cloth can be tweaked further by moving (and keying) the
cloud of empties on scene layer nine. Proogs armature
(proogskel) and jacket armature (proogjakskel) have
controls on armature layer 11 to animate the collar and
sleeve manually. And thats it: youve learned to keyframe
a walk cycle, refine it, and added secondary motions. Now
experiment for yourself to develop the animation further.
STAGE THREE |Layering more actions on top of the walk
You can also add an entirely new action and edit it
on top of the NLA animation. Lets make Proog peer
around. Go to the Action Editor, which currently
shows whatever action is active, click on the x to the right
of the name, then on the arrows for selecting an action,
and choose ADD NEW from the menu. Call the new action
something descriptive: we simply called it peer.
23Now lets refine the animation. To add another
action on top of the path animation, [Shift]+[A] in
the NLA view (with Proogs armature selected) and
add an action by name. Select the crouch action and click the
Add button, then make the Blendin and Blendout 15 frames
or so. Proog will now crouch a bit as he walks.
22
In the left column of the NLA window, hit [Alt]+[C]
to convert the action to a strip. You can continue
to edit from here while viewing the results in the
3D Viewport. Over the range of the action, the new keys
replace the underlying walk, which is usually what you want.
Experiment with what youve learned so far to keyframe a
suspicious peering action for Proog for yourself.
25 26
EXPERT TIPAnimating the faceYou can also add facial animation!
In the proogskel armature on layer
nine are Proogs facial controls.
The controls (nicknamed bots) are
mostly location controls, and are
locked, allowing them to move only
in useful ways. Move around the blue
shapes and youll see their effect on
the face. You can scale botbrowmid
and botnarrow to wrinkle the brow
and purse the lips. The green eyelid
controls can only be rotated about
their X-Axis to raise and lower each
eyelid. The eyetracker (shaped like
a pair of sunglasses) controls the
direction in which Proogs eyes point.
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