Friday, March 21, 2008

Perception is Reality

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Joshua Tree California © Rick Chapman 1999.

I would like to quote an author named Robin Williams, (no not that famous actor and comedian, but a woman living in Santa Fe, NM who happens to share the same name).

-- quote --

The Joshua Tree Epiphany
by Robin Williams

Once upon a time, Robin received a tree identifying book where you could match a tree up with its name by looking at its picture. Robin decided to go out and identify the trees in the neighborhood. Before she went out, she read through part of the book.The first tree in the book was the Joshua tree because it only took two clues to identify it.

Now the Joshua tree is a really weird-looking tree and she looked at that picture and said to herself, "Oh, we don’t have that kind of tree in Northern California. That is a weird-looking tree. I would know if I saw that tree, and I’ve never seen one before."

So she took the book and went outside. Her parents lived in a cul-de-sac of six homes. Four of those homes had Joshua trees in the front yard. She had lived in that house for thirteen years, and she had never seen a Joshua tree.

She took a walk around the block - at least 80 percent of the homes had Joshua trees in the front yards. And she had sworn she had never seen one before!

The moral of the story? Once Robin was conscious of the tree, once she could name it, she saw could see it everywhere. Which is exactly my point. Once you can name something, you’re conscious of it. You have power over it. You own it. You’re in control.

-- end quote ---

So, why am I including this quote from graphic design and typography author Robin Williams? Because her little story about suddenly discovering the joshua trees in her neighborhood as a young girl is relevant to anyone learning something new about the world that has already been seen, and lived in, for one's entire life.

All artists have to rediscover what seems like the obvious, and each one of us has our own approach. No one way is THE right way.

-e

Quick Pencil Test

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Just playing around with various 2D capture setups at home. I decided to animate something, and unlike what I have been preaching for a while, I decided to just improvise and see what came up.














A little improvised waiting sequence with change of focus at the end.


I have a little reversal here. I'm playing with how to keep a simple pose alive while making sure that the small repetitive head scratch has a little texture.

I know its only a quick, rough pencil test but boy do I need to get back into life drawing sessions.

-e

Wednesday, March 19, 2008

Basic Walk Cycle, part 2

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<- go to Part 1: Creating Extremes













This is the second installment on applying information found in The Animator's Survival Kit by Richard Williams to creating a 3D (CG) character walk cycle. The first installment covered creating the first poses or extremes using a pose to pose method. That tutorial touched on the subject of process but mostly concentrated on how to craft visually appealing contact poses or extremes albeit with a not so pretty character. This installment will cover a little more on process while describing how to approach a second pass in the animation process in which I create the primary breakdowns for this walk cycle. Like Richard Williams' we will call these breakdowns the passing positions.

Pass 1 Complete: Timing Poses





















Contact (or the timing) poses. Frames 1 -3 from left to right. I spaced these out to demonstrate a dynamic or progressive walk cycle can be made from this static, treadmill, "on-the-spot" walk cycle.

The first pass in this animation process establishes the extreme poses. Think of the extremes as primary timing poses. Once the walk cycle is complete, the number of frames between these poses will establish the tempo. The second pass will establish the primary spacing poses, or the positions that define how the character moves from one extreme to the next. As stated in part 1, if you alter the contact pose at either the beginning or end of the cycle, make sure to update its complimentary pose at the opposite end of the cycle. First and last poses have to be identical.






Part 1 involved only three frames in the time line, no less, no more. (click to enlarge)

One part of the process that I glossed over in the last tutorial involved having only 3 frames viewable in my time line. I was creating 3 extreme poses and so only needed three frames in the time line. Frame 1 = first contact pose (left foot forward), frame 2 = second contact pose (right foot forward), frame 3 = exact copy of first contact pose (left foot forward). This approach to the time line causes Maya to show you only the poses you have created and nothing more. I learned this approach from Keith Lango who has a wonderful, and very affordable, monthly video tutorial service. I subscribe to Keith's VTS and recommend it to anyone interested in accelerating their growth and understanding of animation. This method of only showing what poses (or drawings) you have created works just as well for mechanical exercises, such as walk cycles, and as well as for acting performances.

Beginning Pass 2: Spacing Poses










Spacing of a ball bounce into and out of the contact point. Richard Williams © 2001

The above image is a section of page 94 demonstrating how the path of a bouncing ball requires a series of drawings that define the arc of its movement and spacing into and out of its contact point. The first drawing to define this arc and spacing is called the breakdown. So, how does this information relate to a walk cycle? During pass 2 of this walk cycle we will create the middle 'drawing' between the contact poses that starts to define the arc and spacing of the movement.















A variety of Passing Poses between identical and generic Contact Poses. Richard Williams © 2001

The breakdown, also called the passing pose for a walk cycle, provides an opportunity to add unique flavor or style in movement. Shown above are pages 112-113 from The Animator's Survival Kit. Richard Williams is demonstrating what opportunities the animator has while creating the primary breakdowns. Log that information away for future use, this tutorial will focus on a generic passing pose (as seen in the upper left page above) for this basic walk. But first, a little more about software.

Software Inbetweens
















Largely symbolic this illustration shows how the computer can precisely split the difference between to extremes. Though undesirable as a final position this can be a useful starting point when creating breakdowns.

If you are new to animating in Maya, change away from Maya's default method for interpolating inbetweens: Clamped Tangents. Do it now! I tell students if I can't explain, at least to myself, the math that creates a curve from a Clamped Tangent then don't use it. I don't have an intuitive understanding of Clamped Tangents so I don't use them. In fact, I have yet to meet anyone who can explain Clamped Tangents without first reading Maya's help files. As animators we don't want anything between our intuition and what we create.

First lets take control of the Maya workspace. Other 3D packages have ways of doing what follows, but this tutorial is only covering how to approach this in Maya.

Animation and Timeline Preferences
Switching your environment settings on the fly is a valuable way to work while animating. Maya gives you a fast get to the preferences in the timeline.











You can find a quick link to your Timeline preferences in the lower right corner of Maya.

Setting up your interface to match your work flow is a goo
d habit to get into. The illustration above shows an easy way to get to your time line preferences while you are working in Maya.

















Maya allows you to override the default settings for playback speed in the timeline work space. (click to enlarge)

Here you see a custom setting of only 2 frames for playback speed. That setting allows you to see the timing of the contact poses... click, click, click, click... two clicks per second. Adjusting your playback speed to show you what poses you have created at the proper tempo can help when working in a pose to pose method. For pass 2 you can change the play back speed to 4 frames per second.

















Creating keys with Stepped Tangents for default out tangent will avoid software inbetweening. (click to enlarge)

In the Maya preferences click on the subcategory of Animation to change how the software is set to interpolate (calculate) transitions between keyframes. Two types of tangent settings useful for early stages of animating in Maya: Linear Tangents and Stepped Tangents. This series of tutorials will explain the value of switching back and forth while using both. Changing the settings in the preferences only changes how new keys get created but keys made with prior settings have to be selected and changed manually.

Dope Sheet Editor
Here is when keying all attributes of you character becomes critical. First you can find the Dope Sheet Editor with the menu command Window > Animation Editors > Dope Sheet... . You will probably want to store a short cut icon to the Dope Sheet Editor on you Custom shelf with other often used commands... just use the menu command while holding down the Control and Shift keys simultaneously. If you have not locked your extremes in place by keying all attributes do it now before you attempt to change the timing of your work.














Inside the Dope Sheet, the short cuts for Move and Scale tools work same as view ports. (click to enlarge)

Select all animated attributes on your character. Open the Dope Sheet Editor. Select all keys found in the Dope Sheet Summery (blue horizontal stripe). Type the r key, short cut for Scale Tool, same as for manipulator in the view ports. You will change timing by scaling the keys over time in the Dope Sheet.














Scaling keys in the Dope Sheet is an easy way to add time between multiple poses. (click to enlarge)

With the Scale Tool active, use the Middle Mouse Button (MMB) to click and hold on the right side of the selected keyframes.... then drag to the right until the 3 keys are spread out over 5 frames. Keyframe data can have decimal values (floating point data) so use the Dope Sheet menu command: Edit > Snap. This command forces all selected keys to whole number frame values.














Newly re-timed contact poses present blank spaces for new inbetweens to be created. (click to enlarge)

The new spaces between keys will allow for software to inbetween your poses if you allow it to. The inbetweens will be mathematically precise but will have little value as animation poses until edited by the animator... that means you.

Graph Editor
First you can find the Graph Editor with the menu command Window > Animation Editors > Graph Editor... . You will probably want to store a short cut icon to the Graph Editor on you Custom shelf with other useful commands.














Graph Editor showing three contact poses with Stepped interpolation. (click to enlarge)

With all animated attributes for the character selected you can frame all keys in the Graph Editor with the f key.














Dragging left the mouse button over the horizontal lines between keys will select all keys on the character. (click to enlarge)

Commands that changes in tangents will only effect selected keys. As with any graphics application, in Maya selection is critical to control and manipulation.














Clicking the button for Linear Tangents creates a linear interpolation between poses. (click to enlarge)

With all keys selected click on the Linear Tangents icon convert to linear tangents. You can also use the Graph Editor menu command: Tangents > Linear. Close editor, click play, watch the ugly inbetweens. Great math, terrible animation.

Using Maya's Inbetweens
So, what did all of that fussing with editors and preferences accomplish?






















OMG! What a laugh! Character's feet floating in the air are a perfect illustration why computers can't be animators.

So what if Maya's inbetweens are ugly, they are still very useful. Maya is moving of a lot of details that you can then quickly adjust as needed. This approach will help create the proper (even) spacing along Translate-Z for a foot that remains on the ground. You will need to correct other elements so that they are not spaced in a boring, mechanical, and even manner.






















A modest improvement is easy to make as are a number of other changes to this first and most important inbetween.

Keep track of which foot is staying on the ground for each frame. The new passing poses will be created on frame 2 and frame 4. Start by removing custom values from the foot control for the foot that needs to remain on the ground for frame 2, and likewise for the opposite foot on frame 4.

Adjusting the Center
In general passing poses, or breakdowns, should not occupy the space exactly in the middle of two keys.






















Adjusting the mechanical passing pose to look natural can be a quick process. (click to enlarge)

Adjust the root or center of the character so that the standing leg is straight. Shift weight towards the standing leg. Tilt hips so that passing side is low. Counter tilt in the hips by tilting shoulders in the opposite direction. Tilt the head as if it is dragging behind the body's weight shift. As stated in the last installment, strive top build overlapping action and drag into your poses.

Checking Arcs
Breakdown poses are a great way to establish arcs in your animation. The Breakdown is usually not in the exact middle between two extremes. The more it is off center the more pronounced the arc.






















IK setups don't create arcs quite as easily as do FK setups. (click to enlarge)

This example uses the IK controls for the hand/arm so the arc in movement must be established by the animator. Simply pull the hand control object down slightly on the passing pose.


Favoring
Favoring is a great way to show weight and momentum in animation. When the breakdown is closer to one extreme it is said to favor that extreme. When creating the passing pose, or breakdowns in general, some elements should favor the prior pose more than others. This is will show weight for that element, as it is taking more effort to move the that part or change the its direction.













Create a position for the rear foot as it passes the standing leg that favors the prior pose. (click to enlarge)


The image above shows how the position of passing foot has been retarded behind the rest of the pose. A common mistake made by many inexperienced animators (especially CG animators) is to allow the passing foot to pop forward from the rear position. The rear foot must take time and effort to changing direction in order to show weight. Refer to my diagram above when I first introduced the subject of software inbetweens versus more organic (human created) inbetweens. This asymmetrical approach to creating poses and movement is central to creating more life like animation.

Standing Leg is Straight





















Straight standing leg also helps to maintain a sense of weight in the walk cycle.

Another important element is to create a straight knee for the standing leg. Lots of walk cycles (especially in CG) look soft and mushy because the standing leg is bent on the passing pose. Later stages in creating a walk cycle provide an opportunity to show how the knees will bend with the weight in the "recoil" and the "overshoot". These poses will be described in the next installment.

Creating Drag
Once again it is extremely useful to create shapes that will assist overlapping action in your sequence. The section above on favoring relates to the subject of creating overlapping action and drag. In general, the rule for creating drag is to have an extremely (such as head, hands, or toes) bend towards the prior position. Bend toes towards prior foot position on the ground. Bend the wrist so that hand and fingers point slightly towards the prior position. Tilt head towards middle position from prior Contact Pose.













Subtle changes in position to drag will add a lot of appeal and weight to your walk cycle. (click to enlarge)

Flip and Roll

There are two ways that traditional animators checked their work while animating: flipping drawings and rolling drawings. Richard Williams describes this on page 81 of The Animator's Survival Kit. One method is for simple changes between a few drawings... rolling, and the other is for testing longer sequences. You have a few options in Maya to do the same kinds of testing.

To "roll" in Maya you need to use a simple key combination to step forward and backward in your sequece. While holding down the Alt key (Option key for Mac OS X users) use the > key (same as "." key no Shift key needed) to move to the next frame, and the < key (same as "," key no Shift key needed) the move to the previous frame. Get use to this method for moving forwards and back... and for the love of God (and your wrists) stop scrubbing.

To Flip through longer sequences you have a few options. Creatinga Playbast (a quick and dirty real-time render) is one option. Or just play back your sequence with the proper 'real-time' playback settings. For that you need the same number of frames in your time-line as poses in your sequence. For this second pass you should have five frames for five poses. With playback settings set to 4 fps click play and view your work from many different angles.... something you can't do so quickly with rendered Playbasts.

Incremental Saving
By saving your work incrementally you are providing yourself with lots of options. First, you are giving yourself a valuable archive of your progress. You are applying one of the most important principles of safety in file management: redundancy. Lastly, you are saving your progress in a manner that is very useful for working under a director. If a director needs you to change your performance you have earlier versions to go back to without having to start over from scratch.

Conclusion to Part 2
Below is an example of the poses created in the first two passes of animation. Unlike the prior animation example in part 1 this example below actually looks like a walk cycle.


Basic Walk Cycle: Part 2 from Erik Westlund on Vimeo.

It's amazing how easy to read this movement is with only contact poses (extremes) and passing poses (breakdowns). The next installment will cover how to create secondary breakdowns that will help to define overlapping action and weight and will spend time on movement of spine and arms.

part 3 is in the works. stay tuned.

-e
<- go to Part 1: Creating Extremes

Saturday, March 15, 2008

Basic Walk Cycle, part 1

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Introduction
part 2 is also available ->

(
Note: skip to Creating Extremes if you hate blog verbiage)


I have been hanging around on the 11 Second Club animation forums for the past couple of months. I genuinely enjoy the vibe of that site. The folks responsible for putting the site together have faithfully carried forward the goal of its predecessor, the 10 Second Club, only better.

One benefit has b
een reading the questions and requests of animation students who are wanting to learn and improve but feel lost when trying to develop skills an understanding. If like me you teach animation, hanging out in the 11 Second Club is a great way to take the pulse of a large community of animation students and prepare yourself for their needs.

One item that
has come up in the forums at the 11 Second Club regularly is "how do I fix my walk cycle?"

As an artist it is very important to pay attention to craft. A walk cycle, whether created in 2D or in 3D (CGI) is just such a fundamental to master... including for animators who like to venture into more experimental approaches of the art form.

























The cover of
Animator's Survival Kit b
y Richard Williams

For anyone interested in the sub
ject, check out the exhaustive description of walk cycles provided by Richard (hasn't he been knighted yet?) Williams. Don't let what looks like simple 2D drawings fool you. There is a ton of information for any animator in William's book. If you own a copy of that book, open it to page 102 and start reading. This post here is largely a rehash of what is included in that text filtered slightly to assist newer 3D animators.


























A generic (vanilla) walk cycle broken down into its parts on page 108. © Richard W
illiams 2001

Above is an example of how Williams explains a walk cycle in basic poses on page 108 of hi
s book. Strangely, the information is neither new, or revolutionary and yet for some reason lots of new animators who crave this information fail to recognized that it is laid out in complete detail in The Animator's Survival Kit. Perhaps the minimalist drawings make people think not much is there. Or maybe it is an example of the Joshua Tree Principle. Regardless of why it gets missed by so many, his book has all you need for a creating good looking walk cycles. Loads of it, and then some. If you are learning animation buy the book or check it out from a library.

I am going to outline some walk cycle construction here and follow up w
ith more detailed information on the subject with subsequent posts. What I am attempting to describe is what to do if you are trying to translate Williams' information into 3D using a character rig available for Maya. For this series I am using a free rig called Geek, created by Kiel Figgins. Model was created by Adam Schuman.

Hopefully users of other software and/or animation mediums will find this helpful
too.

Also, I will describe a work method as well as what NOT to do. This information is based creating countless walk cycles for demonstration and viewing a much greater number of walk cycles from first time animators. First, some basic terms and assumptions...

Timing and Spacing
Working in a pose to pose method allows you establish your timing early in th
e process of creating an animated sequence. After your timing has been established you can then create the poses that will define the spacing between your timing poses. The spacing poses will depend on your timing poses so you must nail down the timing poses first. Fussing with inbetweens comes much later in the process and is entirely dependent on the quality of poses you create first. We will start with the timing poses only.

So, what constitutes a timing pose? A timing pose defines an extreme in the movement
that occurs at a specific moment. In this case, we will use the moment when the heel of the front foot first contacts the ground. We will call this pose the contact pose. We will not be using the term key pose for this because key poses are story telling poses and not necessarily extremes in movement. This distinction also comes form Richard Williams.

One additional note, this will be a stationary (treadmill style) walk cycle. Most 3D animators start with this type of walk cycle, most traditional 2D animators don't. Different mediums sometimes require different approaches to the same goal.

Animating in Passes
This work method allows you to start with the most important el
ements first, leaving less important details until later. For a great description of animating in passes check out notes on how Shawn Kelly organizes his work flow. This post is a description how I create my first pass for a normal 3D walk cycle exercise. Later posts will cover later animation passes in my process.

Creating Extremes
Although animating for 24 frames per second, I start by limiting my work environment to only three frames in the time line. This is an easy way to make sure my animation only contains poses that I create and nothing more. Ultimately, the cycle will be 24 frames in length (from frame 1 to frame 25) and will include two steps. First, create a contact pose, then an opposing contact pose, and also create a copy of the original contact pose.

For a seamless loop first and last poses in the cycle must be identical. Any chan
ges made to the first pose must also be made to the last since they are in fact the same.





















A generic contact pose demonstrating a modest gait for the character.

Start with the feet and hips of yo
ur character. For all walk cycles, keep the angle of the legs, and distance between the feet modest. A giant gait in a walk is unnatural and will look awkward. In general, if it is difficult for you to move or hold yourself like your character is posed, then the pose is wrong and should be adjusted. A natural walk, or even a unique walk, will have a modest gait... to do otherwise will create poses more appropriate for a run cycle.



















Creating a good contact pose requires balancing the feet positions with the hip position.

Using a 3D rig with IK (inverse kinematic) legs means that the knees are controlled by where you place the feet relative to the hips. If you move a foot, you will have to adjust the hips as well. If you adjust a custom foot control that lifts the toes, bends the ball, or lifts the heel, the knee will change angle accordingly. You have to balance all of these elements by watching the shape created by the different parts in combination.















Changing small details such as the angle of feet will improve you contact poses.

To avoid giving your character a robotic look turn the feet outward for the default positions.





















Front leg must be straight at the contact pose.

Shape change is a hugely important subject in animation, and yet for some odd reason it rarely gets discussed. Your initial pose, the contact pose, will set up a shape of your character that will change, giving the necessary perception of weight and solid forms. What you are setting up in the contact pose is stretch of the front leg. This will be followed by squash of the font leg with a later part of the process with a down pose.

Create a Unified Whole, Not Separate Pieces
It is extremely important to remember that this is supposed to be a living be
ing, not an assembly of parts and pieces. You have to pay close attention to how the connected elements influence each other.





















While hips twist only a little, they are not locked in one spot while the feet move forwards and back.

For instance, if the
left foot is forward then the left hip will also be forward.





















A small amount of counter movement will ad a lot of flexibility to the torso.

If the left hip is tilted up slightly, then the left shoulder will have counter balance this by tilting down. In general the shoulders will move in opposition to the hips.

Start General, Work Towards Details
Line of action (some animators call it path of action) is a central line the moves through the character and defines the direction, attitude, and speed of movement.





















It is important to establish a clearly defined line of action on your first pose and craft the details of your pose to match that line. A forward tilt in the line with create a sense of forward movement.





















Creating a line of action that has a slight arc or bend helps to give your character pose more life-like appeal. In most cases, and especially for this type of exercise you should avoid putting a sharp bend in the line of action.

Touch Everything, Key Every Attribute
While creating your initial extremes you should key all att
ributes of your character. If you don't later in the process the software will inbetween some elements differently than others giving you very unpredictable results. Keying all attributes establishes what position you want all elements of you character to have relative to each other for that one pose.





















The default position for most hands on 3D rigs is usually flat, like a pancake. Its unappealing and leaving such details untouched on the first pass doesn't save you any time in the animation process.

You should define the pose of your character down to the finger tips.





















Create a relaxed pose for the hand early in the process.

Posing the hands and fingers into to something that resembles a natural pose will speed up the process of creating such details for pose created later.

Your process in 3D animation has to eliminate opportunities for the software to create movement or poses without you. Learn how your rig is setup and use its structure to key all elements simultaneously. The Geek rig for instance is setup to have a single node called "Geek_CTRL" that drives virtually every other attribute on the rig. Keying all requires that you pay attention to what position exists for each element, lest you allow the rigs default (stiff/rigid) positions to define your work.

Build Overlapping Action into Your Poses
You will want all forms in your character to appear flexible. Flexibility can be a challenge to create in animation and especially in 3D. An important element of overlapping action in a walk cycle is the difference between the arms and legs. While the legs reach an extreme at the contact pose, the arms don't. They will reach an extreme in their swing on the down pose which we will create later.





















Fingers and hands should drag behind the movement of the arms.

One primary way to make a character appear flexible is through overlapping action and "drag".





















A very small amount of change in finger positions can ad life to your walk.

Drag is a term used to describe how some smaller elements resist, or stay behind the larger movement... they get dragged along, so speak.





















Feet can demonstrate drag as well.

Most often drag shows up in the extremities of the character: hands, toes, and head, etc. although it can also influence the center or core of the character as well. Later installments on this subject will demonstrate some of this.

Things to Avoid in Your First Pass
1. Front knee bent on the contact pose.
2. Large, awkward, and unnatural gait.
3. Perfectly vertical line of action.
4. Stiff and lifeless torso.
5. Straight arms, flat feet, and toes.
6. Default, stiff, and flat pose for hands and fingers.
7. Extremes for arms on same frame as for feet.
8. Rushing this first pass.

Conclusion to Part 1


Basic Walk Cycle: Part 1 from Erik Westlund on Vimeo.

Here is a simple example of the contact poses from several angles after they were timed out for 2 steps per second which is an average, "business-like" walk.

If you actually read Richard Williams' book you will learn a lot more than walk cycles. He explains how such fundamental concepts as timing and spacing affect everything. He also explains priorities, as in what to start working on now, what to leave until later. If you want to get going in animation, read his book. I tell students to sleep with it under a pillow. It gets a laugh, but also makes the point that there is a lot of information to absorb from his text.

Oh, and like a skilled musician, practice your "scales". I tell them than too.

If you are just curious about this subject and want more right now, check out some excellent alternative explanations for creating walk cycles:

Dermot O' Connor

Mike Brown

Larry Lauria

Greg Kyle by way of Shawn Hull

Andrew Jaremko

UPDATE [03.01.10]: Or purchase the newly revised edition of Richard Williams' manual at Amazon. For those who truly love geeking out on this stuff Richard Williams has animated the entire text. Check out this nifty little line test of the cover art being brought to life.

Part 2 is now available. Jump to part 2 in this series ->

-e