Computer Graphics Character Animation (CG-CHAR)

FREQUENTLY ASKED QUESTIONS


Compiled By:
Michael B. Cometcomet@comet-cartoons.com

Contributors:
Armando Afremando@mobius.net
Bobby Beckbeck@pixar.com
Jeremy Birnhttp://www.3drender.com/
Jasper Brekelmans  jbrekel@wxs.nl
Darcy Brookerdarcy_brooker@yahoo.com
Jeremy Cantorjeremy@spimageworks.com
Michael B. Cometcomet@comet-cartoons.com
Ken Copepinhead@ozcot.com
Tony Deandeantony@mattel.com
Nelson Deweyndewey@coastnet.com
Steph Greenbergsteph@primenet.com
Stephen GurbanStephen@calc.com.au
Jim Houstonjim@power.net
Angie Jonesangie@oddworld.com
Jo Jurgensjjurgens@online.no
Doug Kelly dakelly@earthlink.net
Keith Langokeithlango@westerncom.net
Bob Lindaburybobl@graphics.rent.com
Rick Mayrick@cg-char.com
Tim Rowlandsontrowlandson@aw.sgi.com
Rob Skiena
-
Glenn Storm
-

FORWARD

This is the Frequently Asked Questions posting for the Computer Graphics Character Animation Mailing list. This posting is designed to answer general questions that newcomers to the CG-CHAR list have.

If you find any errors or have answers to other frequently asked questions that you would like to have included in this posting, please send e-mail to: comet@comet-cartoons.com. If you do correct something or have a change please include the relevant section so I can find it and paste it into the FAQ.

Please note there is a Copyright, Disclaimer and Bibliography at the bottom of this document.

- Mike C.


SPECIAL THANKS

A special thank you to all the members on the CG-CHAR list who help contribute and provide information on a regular basis. It is all of you who make this FAQ possible.

In addition I would like to thank Rick May for running and maintaining the CG-CHAR mailing list. Keep up the great work!


ISSUE INFORMATION

DateApril 02, 2001
Issue Number  8
What's NewFinally Updated! Yay!
Section 1, #2 - Corrected link to Animate List Site
Section 1, #4 - Added info on codecs and compression
Section 1, #5 - Updated U.S. Copyright website link
Section 3, #9 - Eye motion facts totally corrected/rewritten
Section 3, #13 - Good animation web links
Section 3, #14 - Some notes about Visual Storytelling
Section 3, #14 - Hero/Quest Story Model
Section 4, #1 - Added 180 Degree Rule definition

I also updated a few of the contributor E-Mail addresses above, though most are probably woefully out of date...



CONTENTS

SECTION 1 - General Information
  1. What is CG-Character Animation?
  2. What is the CG-CHAR Mailing List and how can I obtain it?
  3. Are there any good books and resources for CG-Character animation?
  4. How can I view sample animations on my system and what formats should I post in?
  5. What can I do to Copyright my artwork?
  6. Is there any information on contracts for freelance work?

SECTION 2 - Demo Reels and Getting a Job
  1. What should I put on my demo reel?
  2. Where can I find video tapes for a demo reel?
  3. Good Ideas When Going to SIGGRAPH
  4. How important are traditional drawing skills? Do I need to draw well to become a CG-Animator?
  5. Jeremy Cantor's Guide to Getting an Animation Job

SECTION 3 - Tips, Tricks and Suggestions
  1. What can I work on to become a good animator?
  2. Is there a good way to work out timing and poses with CG-animation?
  3. Steph Greenberg's Stages of Character Animation
  4. What are some key elements of successful character animation?
  5. The 5 "O's" of Story development
  6. What are the general rotational limits of human joints?
  7. Helpful information relating to the basic principles of animation
  8. Jeremy Cantor's Explanation of Realistic vs. Cartoony Character Animation
  9. Interesting facts about eye motion
  10. Help on Lipsync
  11. Bobby Beck's "Boom! Animation!"
  12. Character Setup Help
  13. Good Character Animation Web Links
  14. Some notes about Visual Storytelling
  15. Hero/Quest Story Model

SECTION 4 - Glossaries
  1. Character Animation Terms
  2. Computer Animation Terms
  3. Common Internet Acronyms

SECTION 5 - Copyright and Disclaimer

SECTION 6 - Bibliography

SECTION 1 - General Information

1] What is CG-Character Animation?

The "CG" stands for Computer Graphics. This means that the computer is used as the medium for creating character animation.

Animation itself is the creation of the illusion of motion. By displaying sequential images one after another in rapid succession items drawn or recorded on the images can appear to move.

Character animation can be defined as animation in which objects or characters are animated to give the illusion of personality, life, and character. This is distinguished from other types of animation such as basic flying logos or visualization since the objects are meant to appear alive and act on their accord rather than simply move.

"Animation alone may move drawings, but it will not move an audience."
             - Glen Keane


2] What is the CG-CHAR Mailing List and how can I obtain it?

The CG-CHAR Mailing List is an E-mail list on the internet run by Rick May. It is designed to specifically discuss CG-Character Animation. There is a web page for the mailing list that includes general information, instructions on how to subscribe, an image gallery, and more at:

    http://www.cg-char.com/

Subscription information is available under "General Information on the List".

If you are interested in traditional animation as well you may also want to join the traditional animation mailing list. See the URL below for more information.

    http://www.perp.com/animate/


3] Are there any good books and resources for CG-Character animation?

The CG-Char web page ( http://www.cg-char.com/ ) has a "book store" with reviews that describe a number of excellent books. In addition most people recommend watching a lot of drawn animation from old Disney films to Warner Bros. shorts and more.

The 3D Ark web pages ( http://www.3dark.com/ ) also have a wealth of information ranging from tutorials to demo reel advice.

ACM SIGGRAPH has recently compiled the most important papers from past proceedings into a single volume. This collection includes John Lasseter's 1987 paper, "Principles of Traditional Animation Applied To 3D Computer Animation." The color reproduction is not great, but at least this essential and hard-to-find paper is back in print. You can contact SIGGRAPH at: http://www.siggraph.org/


4] How can I view sample animations on my system and what formats should I post in?

Many times on the CG-Char list people will place sample images and animations on the web to view. When doing this one should be aware that there are a variety of computer types used by everyone on the list. People may be using anything from SGIs to PCs.

In general when putting up an image the JPEG format is standard. You may be able to post Targa's (TGA) or some other format, but JPEGs are generally smaller and almost every system can view them.

For animation Apple's Quicktime format seems to be the most accepted. While Windows AVI format is also used a lot many people that use PC's.

One important note!: Do NOT send images/animations/attachments to the CG-Char list itself! It is fine to post a message pointing to a web site or FTP address to use to find your work, but do not actually send the images to everyone on the list.

PC-Windows Help
FormatHow To
Apple Quicktime Go to http://quicktime.apple.com/ to download software to playback Quicktime movies. See http://www.QuickTimeFAQ.org/ For QT help.
Windows AVI Built into Windows/95/NT O.S. Use "media player" to view.
MPEG Search the web for free MPEG players like Windows "VMPEG" program
Format Conversion Intels web site has a free utility called SmartVid for conversion of movie formats. See: http://www.intel.com/pc-supp/multimed/indeo/smartvid.htm

Also MainActor available for 95/NT and also Amiga systems can convert MPEGs, AVI's, MOV's Amiga Anims and more back and forth. Available as shareware at shareware sites or look at the developers webpage at: http://www.mainconcept.de/

Macintosh Help
FormatHow To
Apple Quicktime Use "movieplayer"
Windows AVI There may be players available on the net. Also there is a freeware "AVI to Quicktime" converter utility at http://www.shareware.com/ one can use. Use http://www.quicktimefaq.org/ for info You can also look for the Indeo Toolkit from Intel.
MPEG Look for a program named "Sparkle" or "play-it-cool" available at shareware.com or also available at: http://hyperarchive.lcs.mit.edu/HyperArchive/Archive/gst/mov/sparkle-245.hqx
http://hyperarchive.lcs.mit.edu/HyperArchive/Archive/gst/mov/play-it-cool-25.hqx
You can also get the MPEG QuickTime extension from apples web site to use with Apple's "movieplayer". If you get MAC-OS ver 8, this extension is bundled in so you can view MPEG's natively.

SGI Help
FormatHow To
Apple Quicktime Use "xanim" available from http://www.shareware.com/ or "movieplayer" that comes with the SGI media kit. Note that movieplayer will not play Cinepak compressed movies without a license.
Windows AVI Download "unzip" to unzip PKZIP'd files if needed. Then use "xanim" or "movieplayer" to play
MPEG "movieplayer" should play MPEG-1 movies or use the freeware "mpeg_play" utility.

A word about small compression, and preferred Codecs from Keith Lango:

I used Astarte mPack on my Mac at home. Evelyn was 384x160 (i think), 24 fps. Audio was crunched down to 96 bits per second and video was something like 43 bytes per second. Basically, I scrunched that thing as much as my heart would allow. But I also highly recommend Media Cleaner. If only I had a copy myself. Used to have it at work years back and loved it. Especialy when you used the pixel sampling algo's on that thing, file sizes go way down.

I try to avoid using any CODEC that won't play on as many platforms as possible. I find that MPEG is the most widely supported format. Macs, PCs and SGI's all play them rather well. And you really don't want the folks on SGI's to be left out of the fun. One, because most major shops are running on them (and thus you want them to see your work I presume) and 2) That's what I'm on at work, the only place I can download these things at any decent speed. :o) Ok so that second reason was a bit myopic, but you get the idea...

Editors Note: As mentioned, as a general rule, MPEG is almost guaranteed to play anywhere. Some people on SGI's can view older quicktimes or avi's but not newer ones. Many people now prefer the DIVX codec for stuff, as it's small and really good quality, but once again, not everyone can see DIVX stuff.


5] What can I do to Copyright my artwork?

From a post by Jeremy Birn, 12/6/97:

For copyright information at the US Copyright Office go to:
    http://lcweb.loc.gov/copyright/

For only $20 you can register any work (or any compilation of multiple works submitted at the same time) and get it stored for you in the library of congress. They will even send you free information packets and forms for registering films, videos, printed artwork, etc. This is made to be easy and affordable enough that no artist has an excuse for not copyrighting their work. The fact that work is copyrighted at the date of creation is only a technicality if you haven't registered the work, which is the only prima facie evidence of the date of creation.

"Prima facie" means big bucks if you have to go to court: this is accepted as proof automatically unless the opposition puts together a case to prove otherwise. Other techniques (like the urban legend about mailing work to yourself) would require a court battle, hiring expert witnesses about the adhesives on the envelope, etc...


6] Is there any information on contracts for freelance work?

It might be worthwhile to check out the book: "Contracts for the Film and Television Industry" by Mark Litwak. There is also an excellent book on the Television world with included contracts for a variety of uses titled "This Business Of Television" by Howard J. Blumenthal and Oliver R. Goodenough.

Looking at one of the boiler-plate contracts in the first book it has several sections:

1. Employment- conditions of employment
2. Form of Work- what is being done
3. Delivery- schedule
4. Performance Standards  - quality expected
5. Compensation- how and when
6. Warranties- the contracter didn't copy or steal the ideas
7. Ownership- work for hire, who owns what
8. Notices and Payment- official contact info for both parties
9. Assignment- agreement can't be passed off to other parties
10. Credit- what credit is provided.
11. Conditions- other conditions
12. Arbitration- how to resolve disputes.
13. Signatures


SECTION 2 - Demo Reels and Getting a Job

1] What should I put on my demo reel?

Most employers will want to see a sample of your animation ability. For this reason it is important to have a demo reel showcasing your work. In most cases this reel is simply a VHS tape with your latest animation work on it. Here are some Do's and Don'ts:

For more demo reel advice you might want to check out Angie Jones' Spicy Cricket website at:
http://www.spicycricket.com/break_into_f.html
It has a ton of information on how to break into the field for animators and TD's.

There's also the 3D Ark website at:
http://www.3dark.com/


2] Where can I find video tapes for a demo reel:

Look under "Video Tape Duplication" in the yellow pages (or business-to-business pages). It's usually just about as cheap (or even cheaper) to have someone do the duplication for you (5 or 10 minute dubs are often $2.50 to $3.50 each including labels and cases, which compares favorably to most retail blank tape prices.)

Tape prices (as well as prices on cases or other supplies) are based on quanitity. But a company like Steadi Systems has just about every make and length and format of video tape you could find. See http://www.steadi.com/

Watch out for the prices of laser-printer video labels, too! (I saw some in an Office Max that were $45 a box!) If you call Arcal Duplicating Supplies you can get 1200 laser-printer VHS face labels for only $15. See http://www.arcal.com/


3] Good Ideas when going to SIGGRAPH:

SIGGRAPH is a great convention for people looking for work. For more information on the yearly show see: http://www.siggraph.org/ The following are some tips for those job hunting at the show.

Other good ideas I've learned the hard way for SIGGRAPH: ;)


4] How important are traditional drawing skills? Do I need to draw well to become a CG-Animator?

This question can raise heated debate on the CG-CHAR list. The answer really depends on who is hiring. Overall having a traditional art background and drawing/design skills definitely won't hurt. However animation is really about storytelling and motion.

Computer graphics is really the purest medium to work with for animation. All the animator needs to do is to time and pose the character. The computer handles the rendering and in many cases someone else handles the design and modelling of the characters.

On the other hand, animation is a visual medium and some argue that traditional skills are important. In addition it may be helpful to sketch out ideas on paper first. In a smaller buisiness the animator may also be involved in character design, modelling and other areas that require basic art skills.

One thing to note is that while there is argument over whether traditional drawing skills are important, there is virtually none over whether traditional _animation_ principles are important. Indeed having a firm grasp of basic animation concepts such as squash and stretch, overlapping action, ease-in/out, and others are crucial for becoming a good animator in general.


5] Jeremy Cantor's Guide to Getting an Animation Job

The best piece of general advice I can give to someone submitting a demo reel:

Imagine that the people who are going to review your work are the busiest, most disorganized and inconsiderate folks on the planet. You want to make it as easy and painless as possible for them to look at your work. Try to avoid anything that might contribute to them not being able to (or not wanting to) review your stuff.

COVER LETTER:

  1. Make it short and to the point. (See previous paragraph).

  2. If you are applying to a particular department, indicate this so we know who should be looking at the tape.

  3. If you were referred by someone, definitely mention this.

  4. Include a list of references. Most of us have had at least one or two bad experiences with colleagues in the past. If you don't steer your prospective employer toward folks who like you, they might stumble upon someone who doesn't.

  5. Avoid adjectives. I'm always suspicious when someone butters up their cover letter telling me how good their work is. "If your work speaks for itself, there's no need to interrupt." I want an applicant's animations to convince me of their talents, not their words.

  6. Check your sppeling, grammur, punkshooayshun & typoez. This may not matter to some people but keep in mind that your cover letter is often your very first introduction to a prospective employer. Don't let your first impression indicate that you don't check your work and that attention to detail is not a priority for you.

RESUME:

  1. Try to avoid listing irrelevant experiences.

  2. Do, however, list skills/hobbies/interests that might be relevant. If you're applying for a job at an interactive house that makes fighting games and you've studied karate, indicate this. Acting/mime/dance/gymnastics/etc are good skills to mention when applying for a job as an animator.

  3. Accentuate but DON'T LIE! If you were a janitor, say "custodial engineer". If, however, you were a grunt animator at a particular shop and one time you made a suggestion to a co-worker and they took it, don't call yourself an "animation supervisor".

DEMO REEL:

  1. VHS. NTSC. It's a safe bet that the place to which you are applying has a standard VHS deck. They might not have a 3/4 deck or a PAL converter though. Don't send CD's or floppies or zip-drives unless you've called ahead and confirmed that they are able to view such formats.

  2. Put your best stuff first. Because of the volume of tapes I need to look at, if I'm not "grabbed" in the first ten seconds of a reel I tend to watch the rest in fast-forward mode until I see something that looks interesting enough to stop and look at in normal speed. Don't let me miss your best piece.

  3. Don't repeat animations. Please don't assume that I wanted to see that particular piece again. I do have a rewind button on my remote. Also, repeating animations implies you have a limited quantity of work and it looks like "filler".

  4. Keep it short. 3 minutes is a general target length.

  5. Include a reel breakdown. Unless EVERYTHING on the tape is 100% yours, it is essential that you include a descriptive list of your contributions to each shot. If you don't I am assuming that you are claiming that everything is all yours. If you have collaborative work on your reel, it is dishonest, annoying and downright criminal to not include a reel breakdown.

  6. DO NOT PUT OTHER PEOPLE'S WORK ON YOUR REEL! This should be the most obvious thing in the world but it happens. Just last week I received a reel without a breakdown that had work I recognized because it belonged to a friend of mine. After requesting a reel breakdown, the dishonest submitter admitted to "having had little to do with" certain pieces on the reel. Since this information was not initially volunteered I had been led to believe that he was claiming to have done those pieces himself. We do not make a habit of hiring deceitful people. My friend is actually considering a lawsuit against this individual. (Can you say "plagiarism"?)

  7. Don't send inappropriate work. A place that does children's educational software does not want to see blood and guts. If you are applying to a creature shop, don't send a tape full of spaceships and camera fly-throughs. This shows that you didn't take the time to find out about the company to which you are applying. Why should we then take the time to find out about you?

  8. Label your tape clearly and put your contact information in the body of the tape. Sometimes tapes get separated from their resumes. Make it easy for us to re-organize our piles.

  9. Pop your tabs. Remember, we are busy and disorganized. I might hit the "record" button instead of the "play" button accidentally. Remember, I'm thoughtless and inconsiderate.

  10. Rewind your tape. We WILL charge you $1.00!

  11. Include drawings on your tape ONLY if you truly think they will help your case. I will certainly be more inclined to want to interview a tape with borderline animations if there are really good figure drawings at the end. Strong fundamental skills are a good indication of someone's overall aesthetic sensibilities. However, don't include bad figure drawings just to demonstrate that you've taken a figure drawing class. Now, I'm not saying that you have to show figure drawings in order to get hired as a character animator, but don't go out of your way to show your weaknesses. It tells me that you aren't a good judge of your own work and will therefore need a lot of supervision.

  12. Show "acting". Let's face it, walk/run/flight cycles alone will not get you hired as a character animator anymore. Mainly because such motions can be easily copied from a variety of sources. Your animations need to convey emotions and thoughts through body language. Example: Don't animate a kid eating a bowl of peas. Animate a kid who hates peas but his mother is making him eat them anyway. If you can tell such a story through timing, posing and facial expressions alone, you will get hired. (I actually rarely have the volume on when watching tapes).

  13. Avoid large, cumbersome packages that are difficult to catalogue, file and shelve. I've seen them bent to fit into boxes. Which of course brings up: Don't send original artwork. It WILL get damaged.

  14. Don't show stuff you don't want to be asked to do.

  15. Wireframes with solid motion are better than fully textured renderings with mediocre motion. (You might accidentally get hired to do lighting!)

  16. Be careful when including work that isn't supposed to be publicly viewed yet. If you are showing me clips from a film that has not yet been released, you are telling me that you'd be willing to show OUR work before it's released as well. Make sure your interviewer knows that you've cleared it with your current/previous place of employ first.

  17. Make sure your tape really shows what you're capable of. I get a lot of tapes from ReBoot/Beast-Wars folks who mention that they have very little time to do a shot and the style is dictated very strictly. Given such restrictions I can't really judge their skills by seeing this work alone. When I get such tapes I immediately request additional work. Include personal stuff as well as professional work. I like to see what you can do on your own as well as what you can do on a team.

  18. Be honest with yourself. If your entire experience with character animation includes nothing more than having pulled off 2 walk cycles, you're probably not quite ready to offer your services as a character animator. Only apply to a place where you truly feel you can do the work.

INTERVIEW:

  1. Be on time. Remember, first impressions are lasting impressions.

  2. Dress appropriately. You don't have to wear a suit, but error on the side of overdressing rather than underdressing. Don't worry, you're not going to insult a prospective employer if you are better dressed than they are. Chances are you will be...after all...they already have the job!

  3. Bring another copy of your reel/resume. Remember, I'm really disorganized, I might not have it handy.

  4. Bring some additional work. Don't let me believe that your reel comprises everything you've ever done.

  5. Be very careful when speaking negatively about a former job or boss or co-worker. This is a very small industry. There's a chance your interviewer knows the person/place of which you speak. I lost a job opportunity myself because of this once.

  6. Watch for trick questions. "Oh...come on...you can show us those shots from that movie that isn't out yet...we won't tell anyone!" Or: "Hmmmm...I see you have 3 months to go before finishing your current project...we could really use you sooner...are you sure you can't just abandon your current team and join us now?" If you do it to them, you'll do it to us.

FOLLOW UP:

Keep in mind it often takes a while before a demo tape gets reviewed. If you haven't heard anything for 3 weeks or so it is okay to call and make sure your tape was received. But don't be a pest.

After an interview, it is a good idea to send a follow up letter thanking your prospective employer for taking the time to meet with you. Don't call unless you haven't heard anything for a while. And don't contact the company repeatedly.

If you don't get hired, resubmit your materials every 6 months or so. Our needs and criteria change all the time. Your skills/style might not have been appropriate for last year's project, but they might be right for this year's.

That's all for now.
Time for me to do some work...


SECTION 3 - Tips, Tricks and Suggestions

1] What can I work on to become a good animator?

The simple answer is animate, animate animate. If you want to get good at animation you need to work on it. In addition here are some other things to do:


2] Is there a good way to work out timing and poses with CG-animation?

With computer graphics it is very easy to tweak animation and poses. However characters are typically complex hierarchies. Like any hierarchy the motion of the bottom objects/parts in the tree depend heavily upon what the main parts are doing. For example, where a hand is positioned in the scene depends on where the arm is which depends on where the torso is which depends on where the character is standing at that point in time.

For this reason it is generally easier to work with the top layer of motion first. Tweak that timing and then work down. For example if a character is going to walk to a table and pick up a glass you should first make sure the timing of the walk is correct before animating any arm motion. If you animate the glass being picked up and then find out you need to change the length of the walk or exact position of the character to help staging, you will generally have to reanimate that glass being picked up. In addition you would animate the hand motion before adding the fingers in.

Overall you can work the timing out on the major sections and then slowly refine the animation until you are done.


3] Steph Greenberg's Stages of Character Animation

The following is an excerpt from a post by Steph Greenberg. Please see the Copyright at the bottom of the FAQ regarding this section.

"This isn't the first time or the last time I'll say this, but here are the 3 stages of character animation, and what separates passable animation from great animation.

  1. Characters move without pathologies that make you think, "Something's just not moving right, here". This first bar is a pretty hard one to reach.

  2. Characters must be able to show believable emotion, even if it is just through body language. If it's only through body language, you're pretty damn good.

  3. Characters must have a distinct personality. Say you have identical twin characters, one good, one evil. You must be able to tell which one you are looking at just in silhouette.

This last one is really, really hard. Think of Lasseter giving those desk lamps personalities. You could tell which was which, even if they had switched bodies. Or if Buzz and Woody had a brain switch, you'd be able to tell it was Buzz inside Woody's body.

Be that as it may, we very rarely, and I mean rarely, get a tape that makes it to #1. So if you have a reel with only character animation on it, maybe a few seconds of it, usually the last piece you did, will show your true potential."


4] What are some key elements of successful character animation?

When working on a character animation here are somethings to watch for and think about:

- The character should convey emotion
Think about: You may also want to look into watching some old silent films and checking out psychology books.

- Timing of movement
Think about: You may want to study cartoon clasics and sports.

In general you should have a good understanding of the basic Principles of Animation.


5] The 5 "O's" of Story development

Here are 5 basic elements of a good story -- your story (short or long; written or visual) should clearly present all of them to your audience.

  1. Ordinary
  2. Objective
  3. Obstacle
  4. Overcome
  5. Outcome

First the characters need to be (1) Ordinary such that the audience can relate to them. Like in Lion King, Simba couldn't wait to be King. This is an ordinary feeling for children. They want to grow up as soon as they can.

Then, your hero/ine has (2) an Objective of some kind. They encounter (3) an Obstacle that makes achieving their Objective difficult or impossible. They find a way to (4) Overcome the obstacle. Then comes the (5) Outcome of their efforts (anticlimax, happy ending, whatever).

Those are workable storytelling basics.. it's up to you to create interesting characters, add details and flesh out the story.


6] What are the general rotational limits of human joints?

There is an easy to read table from George Maestri's book online the 3d Ark at: http://www.3dark.com/articles/humanjoints.html


7] Helpful information relating to the basic principles of animation

When learning to animate, one of the first things to do is to start studying the 12 basic prinicples of animation. The following is a list of these basic prinicples. Their descriptions are given individually at the bottom of this document under the definitions section. Following these traditional principles are some additional ideas that may be helpful when learning to animate, courtesy of Ken Cope and Jeremy Cantor.

12 Basic Principles of Animation:

  1. Squash and Stretch
  2. Timing
  3. Anticipation
  4. Staging
  5. Follow Through and Overlapping Action
  6. Straight Ahead Action and Pose-To-Pose Action
  7. Ease In and Out (or Slow In and Out)
  8. Arcs
  9. Exaggeration
  10. Secondary Action
  11. Appeal
  12. Personality
Additional "Principles" for Learning Animation:
0. TRULY UNDERSTAND THE BIG 12
I list this as number zero because I think it is absolutely the most important. I find a lot of folks who painstakingly memorize and study the 12 basic principles to the point that they can rattle them off the top of their heads at a moment's notice. However, MEMORIZING a set of rules and UNDERSTANDING a set of rules are two very different things. Understanding means knowing when and where to apply them (if at all) and how much. You don't necessarily want to incorporate all twelve into every performance. Some are simply inappropriate in certain situations. I too often see blind implementation of the rules which result in things like squash & stretch being applied to bowling balls. Or too much anticipation given to a cat doing a jump. (Because of its weight to volume ratio and the fact that its skeleton is already in an anticipated pose, a cat doesn't need to crouch before leaping. It simply extends from its already crouched default pose.)

If a director tells you to make your character look heavier, believe me you are not going to find the answer to doing that by simply reading the list of the big 12. It ain't on there. Rather the answer is found in truly UNDERSTANDING the 12 principles and combining several of them effectively.

Once agaim truly understand the big 12. Everything else is using some or all of those 12 principles towards solving trickier problems. I'd almost want to call them parts of speech in an animator's vocabulary. I can name a couple of problems that a working familiarity with the big twelve can help you solve.

13. WEIGHT
This is really a function of properly addressing 1(Sq&Str), 2(Timing), 3(Anticipation), 4(Staging), 5(FollowThru/Overlap), 7(Slow in/out), 8(Arcs), 9(Exaggeration) and 10(Secondary) but I think it deserves its own category especially since it's something that is very often lacking in a lot of CG character work out there.

14. POSING (& anatomy)
This is more or less a sub-category of "staging" and "appeal" but, again, it is so important that I think it should be listed separately. Not to be confused with number 6 (pose to pose vs straight ahead) which merely addresses the difference between the two methods. What I'm talking about is paying close attention to anatomy (understand the underlying structure) and "appealing" poses. Watch out for center-of-gravity placement, off balance problems, too much symmetry and such.

15. NON-SYMMETRICAL POSING & PERFORMING
Again, more or less a sub-category of "appeal". This is as well something I'd definitely list under the category of "Most Common Character Animation Blunders" (another thread) and therefore deserves to be on this list. Watch out for poses where the left half of a character is a mirror of the right (Twins) and animations where (for instance) both arms hit their extreme poses on exactly the same frame (also Twins). Break it up.

16. PLAN AHEAD
Hopefully this doesn't need much elaboration. (Editors Note: See Bobby Beck's Bang! Animation! section)

17. BLOCKNG/REFINING
I'd also extend #6 (Straight Ahead vs Pose to Pose) to incorporate a third method of animating (which applies mainly to CG). Blocking/Refining. Where you get your basic timing and trajectories worked out first. Then work inward toward the details. Kinda like doing a painting. Broad strokes first to get the overall composition and colors, then use increasingly smaller brushes to hone in on the details overall (rather than finishing one corner then moving to the next).

18. INTENTIONALITY
The absence of this item results in characters looking "moved" rather than "moving." I want to see the character move as a result of its own apparent intentionality, not just because that's where the animator put it.

This was inspired by Bobby's Ollie quote in his sig: "Don't move anything unless you understand its purpose."

If everything is moving for a specific reason, the movements are more likely to appear to be externalizations of an internal thought process, yer classic personality animation. If the intentions, the goals behind all of a character's movements can be clearly read, there won't be room for any cues that read false. Mastering this makes the difference between a character that has been posed, and one who strikes a pose.

With a character's actions and reactions to its environment you can show that it behaves with intentionality, and get inside its thought processes.

More elementarily, if a sleeve should drag when a hand changes direction, and you make no provision for moving it the way it should move, you have violated the intentionality of that sleeve ("wanting" to behave according to its inertia) by making it do something it would not have done ordinarily, making it look like it was something you did instead of the sleeve doing it.

19. ISOLATION
This comes from a dancer's vocabulary, the ability to isolate, say, a shoulder movement from what the head is doing... or hips from the shoulders. Too frequently, habits acquired from early days or restricted subsets of animation tools make us settle for artifacts of setup that hamper the ability to place and time the movement of a body part where and when we want it, merely because its parent is in the wrong place, or moving the parent would disturb too many children and it's too late to revise now. Strange epicycles are the result, instead of good arcs.

Your planning must be rock solid to animate without the capacity to revise the position and timing of any part of a character without fear of destroying a ton of work. If a puppeteer can move a character's hips, leaving the knees and shoulders in place, as easily as can a pencil animator, why should it be harder in CG? Isolate the timing, as well as the position, from other parts of the character and points in time-- goals that rigid, top-down heirarchies make difficult.

We CG Char types paint ourselves into a lot of corners and live with the results, hoping to apply what we've learned to the next task. They're just different corners than cel or stop motion.


8] Jeremy Cantor's Explanation of Realistic vs. Cartoony Character Animation

Realistic style animation requires exacting attention to real-world gravity and physics (especially when you are compositing a CG character onto filmed background plates). Cartoony style involves exaggerating and/or de-exaggerating such things (and occasionally even breaking such rules). Increasing snap. Bigger, longer anticipation holds. More extreme follow through. Exaggerated squash and stretch. Longer holds at the extremes. Generally fewer actual extreme poses. (Elegant simplicity you know), etc... Often with cartoony style work the animator has some artistic license to adjust physics and gravity to what looks appealing...

HOWEVER, in both styles, once the physical reality has been established, internal consistency must be maintained.

Keep in mind that the fundamental principles of animation apply equally to both styles, just in different ways. Cartoony style sometimes involves intentionally ignoring a rule, but it is extremely important to UNDERSTAND the rule you are breaking in order to break it effectively and with appeal.

A character being "cartoony" is by no means an excuse for not paying attention to center-of-gravity issues and indication of weight. Those issues need to be there. The difference lies in how they are applied.

With regard to technique, we find that (and this is definitely a generalization) realistic animation has more to do with proper attention paid to the smooth, realistic transitions BETWEEN poses while cartoony style is more about the poses themselves, sometimes with rather limited regard to how the character got to that pose. (And I certainly don't mean to imply that posing is less important in realistic-style animation - I'm simply saying that there is more emphasis on the extremes with cartoon-style). Realistic characters tend to smoothly flow through poses while cartoon characters tend to snap into and hold their poses longer. Real characters certainly can move quickly but they can't start and stop on a dime like a cartoon character can. Cartoony anticipation and follow through tends to be EITHER much more than in real life OR much less than in real life.

Watch old Warner Cartoons and you'll see that much of their characters' animation involves not much more than keyframes on the extremes with just a few in/out frames on either side of each extreme pose and very little of what we'd define as "in-betweens". Snap into this pose. Hold. Then snap into that pose. Hold. etc...


9] Interesting facts about eye motion

Just as you can read a thought or feeling from someones body langauge, eyes also play a key role. The following are some guidelines that have been discovered.

The following has been updated from the following page, which also has a nice diagram showing eye angles and what they are related to at:

http://www.tradey.com.au/darcy/eyel.html

Eyes or "windows to the soul" as gypsies referred to them can reveal our fears, desires, attitudes, sincerity and many other elements that we often cant or wont communicate through words and actions alone.

Verbal communication, which includes rhythm, pitch and tone as well as the actual words we use, only accounts for about 20 to 30% of our total communication efforts. This leaves a pretty hefty chunk of the communication up to body language. More interesting is the fact that people only make eye contact about 20% of the time. So what are our eyes doing for the remaining 80%? The answer: a volley of movement as we switch in and out of different modes of information recall (recalling past experiences) and construction (creating new information from previous experiences).

According to the experts whenever we look to the left we are recalling information and to the right we construct. Something that must be taken into account is the fact that a small percentage of usually left-handed people are wired in the opposite way. Psychologists will often perform some kind of calibration before examining a client by asking leading questions to learn how their eyes behave.

Try the following: Ask yourself what colour your car is and take notice which direction your eyes are looking.

Up: Looking up (whether to the left or right) is the visual area. E.g. remembering car colours (up-left) or making them up (up-right).

When we recall visual information we look diagonally up to the left. On the other hand, when we look up to the right we are constructing visual information. Both visual and auditory construction have often been mislabeled as lying; this is only half true. Up to the right indicates they're making things up but does not mean lying necessarily as they may be guessing or confused and not actually intending to deceive. Looking directly right means possibly constructing sentences - ie telling the truth but not sure how to word it. As you can see lying is not as black and white as someone just looking diagonally up right or directly right.

It has more recently been discovered that people close their eyes briefly before giving a false answer.

There is also a small percentage of people with what is called the thousand-mile stare. These people look like they are looking right through you when communicating but actually require very little eye movement when retrieving or constructing information.

Middle: Looking directly left or right is the auditory area. E.g. remembering what was said (left) or making a new sentence (right).

Down: Looking down left and right is the kinesthetic or feeling and emotion area. Feelings and emotions are expressed when a person looks down diagonally right. Diagonally down left is internal dialogue. You may recall when Buzz Light-year realized he was only a toy how he looked down searching his feelings.

Confident people usually make more frequent eye contact when communicating. Nervous and surprised people can be wide eyed while untrustworthy and defensive people will often squint and dart their eyes from left to right. Open and warm communicators may also appear to be wide eyed which can also be a sign of intelligence or attentive listening. Open communicators will also make use of smiling eyes. In contrast an angry person may stare with squinted eyes for an uncomfortable length of time.

Is he/she interested in me? Ever had someone look you up and down? When the opposite sex, an employer or enemy first approaches you they may look you up and down to size you up. Men will also often glance at a woman's breasts when communicating, hmmm the statistics on that would be interesting to see.

As you can see there is a great deal of information being communicated through this window to the soul and a good understanding of eye-movement is an invaluable tool for the character-animator. While body language can be difficult to interpret it is vital to communication and can weigh more heavily than words.


10] Help on lipsync

There is an article on basic lipsync that should be useful to beginners and perhaps others. It is available at: http://www.comet-cartoons.com/toons/3ddocs/lipsync/lipsync.html

In addition one might want to read some traditional animation books as listed on the CG-Char web pages, or Doug Kelly's "Character Animation In Depth" book, George Maestri's "Digital Character Animation", or "Animating Facial Features & Expressions" written by Bill Fleming.


11] Bobby Beck's "Boom! Animation!"

Boom!

Animation stuff:

Things I've been learning

  1. I've been taking a traditional animation class and I am stoked. Man, this is the best thing I've ever done! The teacher keeps talking about the "center" of the character. We are the character. He said, Make it personal!!! "We are the character! How would WE react to this situation?!" Boom, my head is going crazy and I love it!!!!! Or take people you know and/or observe and interject that into your work. Man, this stuff is real! Make it sincere.

  2. A good idea?

    Where do you get ideas? man this is the hardest thing. I usually have one or two good ideas, thumbnail poses then get to it. He was saying the tendency is to just jump in and start. He did it for years. But he Heard Crazy amazing MILT KAHL speak and he said it changed his life! Milt would do PAGES of thumbnails for just one action! BOoommmM! pages!!! No wonder that dude was one of the best! That's the only way you are going to get the best stuff. Exploration!!!!!! Explore! Explore explore!!!!!! Frank and Ollie used to show their stuff to janitors to get input! Man, that's great! Show everyone and get more ideasss!!! Whoooasaaaaa I'm going crazy here!!!!!!!!!

Okay, so I'm stoked and I wanted to share. This is probably all the "secrets" of animation that there are! Man that's it! I guess I just needed to say it, now it's time to put that action to the test!

Bobby Beck


12] Character Setup Help

Probably the best advice for anyone trying to setup a character is to suggest that they really study anatomy. There's no question that setup is an art unto itself. There's skeletal issues such as where and how the joints rotate, there's deformation issues such as how does the muscle or mesh properly animate, and there's the issue of making it all simple and easy for the animator to work with. It's no wonder that the bigger houses tend to have a separate job for character setup technical directors.

Listed below are several good anatomy books with a small descrption for each provided by Angie Jones.

Anatomy Coloring Book
by Wynn Kapit, Lawrence M. Elson
Price: $ 15.98
ISBN: 0064550168
**This is the ultimate book out there!!!

Even the masseuse here, recommended it for learning all about the muscles, skeleton and their connections. You simply color in the areas of each page and then color the name of that group with the same color. Its kind of a *hands-on* thing that helps you learn how the body moves and works. It also has every part of the body separated, so you don't see a shoulder area with ALL of the muscles at once. There are simplistic explanations for the many types of joints too! I cannot believe that 3D software has not been set-up with regard to the skeleton before! If the software developers actually looked at this book they would see the many types of joints...ball and socket, hinge, saddle, ellipsoid, pivot and gliding! All of these should be available functions of IK solutions that you can use to create you skeleton. For now we just have to think of work arounds to emulate these motion. Bottom line, get this book and study it! You will become a better animator and create better skeletal set-ups.

Melloni's Student Atlas of Human Anatomy
by June L. Melloni (Editor), Ida G. Dox, H. Paul Melloni, B. joh Melloni
Price: $34.95
ISBN: 1850707707
**Great basic book that covers it all on layers.

This book is also a great learning tool. It offers pages of each muscle, its origin of attachment, the insertion on the skeleton, and its action. You can easily use this book to set-up complex relationships between your skeleton and your deformation tools to create the muscle movement that happens when joints flex.

Albinus on Anatomy : With 80 Original Albinus Plates
by Robert Beverly Hale, Terence Coyle
Price: $11.16
ISBN: 048625836X
**More layers here.

Great reference, plus just a beautiful book with the illustrated plates inside. Orders the muscles into 3 layers. Each section starts with skeleton, first, second and then third order of muscles.

Color Atlas of Anatomy : A Photographic Study of the Human Body
by Johannes W. Rohen, Chihiro Yokochi, Elke Lutjen-Drecoll
Price: $62.00
ISBN: 0683304925
**If you have a weak stomach, don't get this book!

If you need a reference for realistic textures of skin, bones and insides...look no further. There are many color photos of cadavers and body parts. We got it mostly for the texture info, but there is also plenty of good info in this one.


13] Good Character Animation Web Links

The following are some sites or articles that may be useful for character animators. Please realize these links are not a part of this document. As such I make no warranties as to the usefulness, safety or quality of these sites. (ok legal jargon done! :) )

CG-Char Mailing List Web Pages
If you not reading this FAQ on the site, visit it. It's the official site for the character animation mailing list.

The Cycle
This is a site with real production people and animators giving their opinions and ideas on different topics in the industry.

The Scratchpost
This is another site with resources such as Animator Interviews, reviews, company listings, job listings and more.

Gamasutra - Game Developer
This is -the- site if you are interested in making video games or working in the video game industry. They have tons of articles and resources for game developers and artists. This is the same site as the printed version of "Game Developer Magazine" which you can also buy in bookstores.

ACM Siggraph
This is a link to the Official siggraph organization. There is a huuuge SIGGRAPH conference every year with people from all over the world attending. It's a great place to go if you are trying to get into the industry (you can interview with many companies there), want to research CG software or hardware, or just want to hang out. Look for the "Conferences" link on their page.

Performance And Acting or Animators - by Judy Lieff
This is an article on AWN that is quite interesting reading for those interested in character animation and acting.


14] Some notes about Visual Storytelling

In one Pixar class, Oren Jacob, a lead TD, shared his notes from a 3 day seminar by Bruce Block, about visual structure.

Visual structure is the use and control of the 7 visual elements on screen (Shape, line, hue, value, space, motion and rhythm) to support the narrative line of the story. In a very small example of one element, notice how editing two shots with motion in them have a different effect, depending on whether the motion has the same or opposing direction from one shot to the next. If the motion is opposed in the second shot, the resulting effect is of higher contrast in the visual makeup, bringing about a moment of higher intensity that hopefully corresponds to your script. The use of CONTRAST and AFFINITY in the arrangement of the elements on frame, or from one shot to the next, will help amplify your story.

Related books:

"In the Blink of the Eye" by Walter Murch
"On Directing Film" by David Mamet


15] Hero Story Model

"The Writer's Journey. Mythic Structure for Story Tellers & Screenwriters" by Christopher Vogler argues that the quest theme is the basis for all stories. This book evolved form the practical notes Vogler put together while at Disney's story department. These notes were largely inspired by Joseph Campbell's "The hero with 1000 faces".

In essence here is the hero's journey model whatever the genre:

ACT I
    ordinary world
    call to adventure
    refusal of the call
    (meeting with) mentor
    first Threshold (skirmish, difficulty etc.)
ACT II
    tests, allies, enemies
    approach to inmost cave
CRISIS
    supreme ordeal
    reward (seizing the sword)
    the road back
ACT III
    resurrection (near death experience or rebirth)
CLIMAX
    return with the elixir


SECTION 4 - Glossary of CG-Animation Terms
What follows are terms you are likely to encounter when dealing with computer graphics character animation. While the definitions here should be accurate it may still be useful to read other materials describing these topics or to discuss these items on the CG-CHAR list.


1] Character Animation Terms

180 degree rule
The 180 degree rule is a rule relating to the staging or blocking of characters or actors, relative to the camera. In the simplest case, imagine 2 characters facing each other in a shot, with a line connecting character A to character B. The camera can be on either side of this line, but to maintain continuity, it should not cross the line. This is called the 180 rule because this line creates 180 degrees of freedom for the camera, but the camera cannot go a full 360 degrees around the character. From the cameras point of view, if say character A is on the left and character B is on the right of the screen, if the camera were to cross the line, the characters would appear to switch sides, and thus confuse the viewer. Typically all cameras for a shot or group of shots should stay on the same side of the line. If a new character enters or leaves, then a new 180 degree line can be created and used.

Animatic
See Also "Storyboard"
Sometimes images in a storyboard are filmed with audio and are timed so each image is recorded for the appropriate amount of time. This produces a sort of pseudo-animation with hard cuts at key points. This is known as an animatic. It is also known as a Leica Reel (original traditional term), Pose Reel or more commonly a Story Reel.

Animating on 1's/2's...
See Also "Frames Per Second, FPS"
Basically 1's and 2's refers to how long a drawing is held when it is shot. (this is a traditional animation term). For example, NTSC video is 30 frames every second. If there is a new drawing every frame (ie: 30 per second) then it is shot/animated on 1's.

However, one could draw 15 frames of animation, and shoot each image twice in a row. This is animating on 2's. The result is the animation is a little more jerky and is at 15 fps instead. However this saves drawing time and the motion in many cases looks pretty decent.

Generally quick fast motion requires animation on 1's or you may lose information. A lot of typical cartoons are on 2's, or even slower. I've seen some anime with keys around 6 or 7 for some shots. As long as the motion is somewhat slow it can work.

For computer animation the software takes care of all the tweens for you. So you are basically animating on 1's all the time, unless of course you tell it to render every other frame, etc...

Animation
The illusion of life and motion typically created by displaying sequential images in rapid succession

Arcs
In the real world almost all action moves in an arc. When creating animation one should try to have motion follow curved paths rather than linear ones.

Anticipation
See Also "Follow Through"
Action in animation usually occurs in 3 sections. The setup for the motion, the actual action and then follow-through of the action. The first part is known as anticiaption. In some cases anticipation is needed physically. For example before you can throw a ball you must first swing your arm backwards. The backwards motion is the anticipation, the throw itself is the motion. In addition anticipation is used to lead the viewers eye to prepare them for the action that follows. Generally a longer period of anticipation is needed for faster actions.

Appeal
Appeal means anything that a person likes to see. This can be quality of charm, design, simplicity, communication or magnetism. Appeal can be gained by correctly utilizing other principles such as exaggeration in design, avoiding twins, using overlapping action, and others. One should strive to avoid weak or awkard design, shapes and motion.

Bar Sheet
See Also "Exposure Sheet"
A form traditionally used by an animation director to time all of the action, dialouge, sound effects and music for an entire sequence or picture. Some people may also refer to this as an exposure sheet.

Blocking
This term comes from traditional theatre where it means figuring out where the actors will be on the set at specified points in the script. For computer animation, the definition is basically the same. Usually blocking means a very rough animation that shows the characters in the scene with a basic set of poses and timing to get a feel for how the shot will look. It can be very very rough as in simple block shapes moving around, or it can be more detailed with actual poses that a more finished animation could be based off of. Blocking can also be defined as: The act of protecting oneself from another animator after giving a scathing critique of their work. :)

Composition
See Also "Staging" & "Silhouette"
Composition of an animation, like composition of a painting, requires an interesting mix of positive space (your subject) and negative space (your background) while providing a clear focus point for your audience to "find" the action within the frame. As a general rule, symmetry in composition is a no-no. It's more interesting to see things out of balance.

Dailies
Animation or footage that has been developed and printed overnight. Many CG houses will render out sequences overnight and then discuss changes needed the next morning in "dailies" sessions.

Ease-In/Ease-Out
This term deals with the positioning of an object between keyframes. In most computer software you can adjust the speed at which an object enters or leaves a keyframe. By making an object slow down as it approaches (Ease-In) or slowly speed up as it leaves (Ease-Out) you can smooth out action. For example, when a ball is bouncing it will slowly come to a stop at the top if its climb (Ease-In) and then slowly accelerate as it rushes toward the ground (Ease-Out).

Exaggeration
The idea behind exaggeration is to accent the action. However it should be balanced and not used abitrarily. One should figure out the reason for an action, or even sound effects, character design etc... and how to exaggerate the needed sections. The result will be that the animation will seem more realistic and entertaining.

Exposure Sheet
See Also "Bar Sheet"
A form an animator fills out that has detailed camera instructions for each frame. It may also have some of the same information as a bar sheet. Also known as an X-Sheet. Some 3D software, especially dialouge/lip sync software have virtual Exposure Sheets.

Follow Through
See Also "Anticipation"
Follow through is the movement at the end of a motion. In most cases objects don't stop suddenly, but tend to travel a little farther past their end point. For example when throwing a ball, after releasing the ball your arm will continue to move a bit. This is known as follow through.

Frame
A frame is the unit of time used in creating animation. Essentially there is 1 image per frame. Each drawing or frame is shown sequentially and the images appear to move.

Frames Per Second, FPS
This is the rate at which animation frames are displayed. NTSC Television in the U.S. and Canada shows 30 images every second, so animation on TV is played at 30 FPS. PAL format used in Europe and SECAM in France uses 25 FPS. Film uses 24 FPS. As a note you can still show animation at a lower rate by using less drawings for more time. That is, if you show every frame of an animation twice in a row and then playback each image at 30 images a second the animation will appear at 15 FPS.

Hold
See Also "Moving Hold" A Hold is a period of time where a character remains in one pose. In general having a character remain completely stationary kills the illusion of life. Therefore holds are usually implemented as moving holds.

Inbetweens, Inbetweener
Typically animation is created by posing an object at a specific position at a given time. The position of an object _between_ any two "key" poses are the inbetween poses. Most computer software allows the animator to create these key poses while the software "inbetweens" the additional frames.

In traditional animators typically drew "key" poses/drawings and the inbetween drawings were taken care of by another animator also called an "inbetweener".

Keyframe
3D animation is usually created by posing a character in a specific way at a given frame. This frame is called a keyframe. Usually you position an object at two different frames and let the computer inbetween the motion between these key poses. In traditional animation the animator usually draws key cels and the inbetweener creates the motion between the poses.

Note that these poses do not need to be the extremes (though typically they are). For example, in releasing a thrown ball the 2 extremes might be the arm coiled back and then out very straight and stretched (for follow-through). Then there would be an additional key frame of the arm coming back to a more natural position but still out (end of the follow-through). So those are 3 key drawings. But the most extreme is in the middle.

Leica Reel
See "Animatic"

Moving Hold
A moving hold is one where a character stays in one basic pose for a period of time but still has some part or all of him subtly moving. This movement can help keep the illusion that the character is alive. Anything from animating a breathing rib-cage to eyeblinks can be used to create a moving hold. In general two very close poses are inbetweened. The result is a slight motion that keeps the character from looking frozen.

Overlapping Action
When objects with loose parts or appendages move these parts tend to move with a different timing than the main section. The difference in timing of these loose parts is known as Overalapping action. For example if a dogs is running and comes to a stop its ears will tend to continue to swing forward and then back, and will stop moving after the dog itself has stopped. This overlap tends to create more interesting and realistic animation.

Another important note is that no action should come to a complete stop before another action is started. Even though ideas should be presented clearly (see staging) there should be some overlap in activity and action to maintain continuity.

Pencil Test
See Also "Wireframe Preview" & "Rough"
With drawn animation each sequence is usually first checked by filming the original drawings. This allows the animators to see any potential problems and fix the animation before the cels are actually inked and painted. This is the same concept of a wireframe preview text in 3D computer graphics.

Personality
This word isn't actually a principle of animation, but refers to the correct application of the other principles. Personality determines the success of an animation. The idea is that the animated creature really becomes alive and enters the true character of the role. One character would not perform an action the same way in two different emotional states. No two characters would act the same. It is also important to make the personality of a character distinct, but at the same time be familiar to the audience.

Pose Reel
See "Animatic"

Pose-To-Pose Animation
See Also "Straight Ahead Animation"
One of 2 basic approaches to animation Pose-To-Pose animation is created by drawing or setting up key poses and then drawing or creating inbetween images. This is the basic computer "keyframe" approach to animation. It is excellent for tweaking timing and planning out the animation ahead of time.

Rotoscope
See Also "Motion Capture"
It is a machine which projects a live actor on film to an animation disc. The device was patented in the 1920s by the Fleischer brothers, and was designed to allow animation to be matched to live action. It was later employed to create cheap but very human like animation which is generally reviled by classic animators.

Rough
See Also "Pencil Test"
Traditionally a rough is a drawing or sequence that shows the general motion but lacks details. With computers a rough is usually a quick first pass animation typically lacking things like finger or facial movement, or subtle secondary and overlapping action.

Secondary Action
Secondary Action is an action that occurs because of another action. It creates interest and realism in the animation. In addition secondary action should be staged such that it can be noticed but still not overpower the main action.

Silhouette
See Also "Staging" & "Composition" & "Twins"
From the camera's perspective, a silhouette is the shape of the subject as contrasted from the background. A "clear" silhouette is one in which you can not only distinguish where the character is in the shot, but what action is being portrayed as well. Keep in mind, that as your camera moves in relation to the character, the character silhouette also changes. And in CG, it's usually not for the better.

Slow-In/Slow-Out
See "Ease-In/Ease-Out"

Snap
Snap is action that happens quicker than the eye, or frame rate. It's the kind of timing that is most associated with "good timing". If you watch your fingers as you snap them, you'll see that it's hard to see the finger in "mid-snap". The most you might see is a blur between the snap positions. To animate something happening this fast effectively requires anticipation (antic) and follow-thru to help convey the action.

Another way to think of this is the character tends to move quickly from one pose to another in only a few frames. Computer animation has a tendency to look very flowing and mushy and it is a good idea to work on timing and editing spline curves to add some snap to your animation.

A note of warning!: There is another term that is sometimes used which is 'Snap and Drag'. This refers to a quick change of direction due to a wave like motion or whiplike motion. For example with a whip there comes a point where the end of the whip is moving outwards while the base mass moves the other way. The tip is essentially dragging behind until it suddenly snaps back the other way. This is known as 'Snap and Drag' and while somewhat related to this definition of Snap, it is not what is usually meant when the term is used on the CG-Char list.

Staging
See Also "Silhouette" & "Composition" & "Twins"
Staging is presenting an action or item so that it is easily understood. In general action is presented one item at a time. If too much is going on the audience will be unsure what to look at and the action will be "upstaged". One important facet of staging is staging in "silhouette". This means that a pose of an object or character can be interpreted even in black and white silhouette. If you can not "read" the pose of a character in silhouette it is not a strong pose and should probably be changed.

Straight Ahead Animation
See Also "Pose-To-Pose Animation"
There are 2 basic methods to creating animation. Straight ahead animation is one where the animator draws or sets up objects one frame at a time in order. For example, the animator draws the first frame of the animation, then draws the second, and so on until the sequence is complete. In this way there is one drawing or image per frame that the animator has setup. This approach tends to yield a more creative and fresh look but can be difficult to time correctly and tweak.

Storyboard
See Also "Animatic"
Storyboards are drawings of specific parts of a planned animation used to visualize the story and animation that is to be created. Typically there is a drawing for any key point or change in camera angle. By looking at each image sequentially one can plan out the shots that will be used in an animation. Drawings can be moved around to change the order or timing.

Story Reel
See "Animatic"

Successive Breaking of Joints
See also "Arcs" & "Overlapping Action"
This refers the idea that a chain of objects linked together will move or rotate succesively one after another instead of all coming into position at the same time. This is similar to a whip-like motion where the base moves, then middle section and then the end. Imagine an arm reaching out to grab something. The base or upper arm would come to extension first, followed by the lower arm and then slightly later by the hand. By offseting keyframes instead of making each part of the arm have the same timing, the motion is more fluid and natural looking.

Note that this is somewhat related to Overlapping Action in that many items animated for overlapping action will utilize a breaking joints type motion. In the dog ears overlapping action example given for that definition, one would expect the ears to smoothly bend with the base reaching forward before the tips...ie: each part of the ear 'joint' is keyed slightly later working down the hierarchy. However, successive breaking of joints can be used for standard motion as well as in the arm reaching sample above.

Squash and Stretch
Squash and stretch is a way of deforming an object such that it shows how rigid the object it. For example if a rubber ball bounces and hits the ground it will tend to flatten when it hits. This is the squash principle. As it starts to bounce up it will stretch in the direction it is going.

One important note about squash and stretch is that no matter how an object deforms it should still appear to retain it's volume.

Another important note is most people try NOT to simply use scaling in 3D animation for squash and stretch. Real squash and stretch is usually some part of an object deforming differently that just a simple scale. For this reason using Bones, FFD's or morphing is usually a better way to go.

Timing
See Also "Snap"
Timing is the speed of an action. Timing is critical in animation because it determines how characters are percieved. For example a character that blinks his eyes fast will appear awake and alert. The same motion slowly will make the character seem sleepy or drowsy.

Tweening
See "Inbetweens"

Twins
See Also "Staging" & "Silhouette"
When posing a character one should pay attention to making sure the pose is not symmetrical. i.e.: a character is not standing with it's weight perfectly centered, both hands in the same position, shoulders and feet horizontal and so on. When a pose is symmetrical and therefore unnatural (and boring) the problem is known as 'twins'. One should try to keep poses asymmetrical and can even do this for things like eyes and blinks, mouth curves, other details and also actions. i.e.: for an action where a character is jumping you would animate one foot or leg hitting the ground before the other so they don't both hit at the same time. The point is that it related to both the pose of the character, as well as the timing of the actions of the parts of the character, or even multiple characters.

A good example of a natural standing pose without twins would be the contrapposto. This is an Italian classic art term, paticularly evident in ancient Greek sculpture. When standing, a human puts more weight on one foot than the other. On the side that has the most weight, the hip rotates up and the shoulder rotates down towards the hips, while the spine is shaped slightly like an arc. This makes the pose appear more natural and less stiff.

X-Sheet
See "Exposure Sheet"


2] Computer Animation Terms

B-Spline
See Also "Spline"
These are a type of spline where the curve passes close to but not through the control points or knots. They are currently popular for use in spline based modelling and are similar to NURBS. With these splines, you're dealing with the hull rather than the actual surface.

Bezier Spline
Bezier splines and cardinal splines have their curve pass through the actual control points. Beziers have handles to achieve this. The handles control the tangent to the curve at each control point.

Cardinal Spline
Cardinal splines and bezier splines have their curve pass through the actual control points. Beziers have handles to achieve this. Hash's Animation Master, uses a proprietary variation of the Cardinal spline. By selecting an Alpha, Gamma, or Magnitude value then dragging the mouse across your screen, you are kinda pulling "virtual" handles (similar to Bezier splines) to adjust the bias of your spline. Hash's splines also lets you create holes in your model.

Chatter
This is a term that can be used to describe a jerkiness in motion. Typically it occurs when an object has too many keyframes close together that are different. This makes the object appear to vibrate. This can occur when trying to manually keyframe feet to appear locked to the ground with out inverse kinematics. The legs may have many keyframes that are slightly different and so it appears to have "chatter".

Forward Kinematics
See Also "Inverse Kinematics"
Foward Kinematics, or FK refers to how a basic hierarchy or chain of objects is animated. With FK, each joint in a chain is rotated individually. In order to pose or position a segment at the end of the chain, each previous link needs to be manually rotated into position. Many software packages in the past only had FK, which meant keeping a characters feet stationary or locked to the ground had to be done by manually rotating the legs when the character moved. Currently, many animators use Inverse Kinematics for feet locking.

Gimbal Lock
With certain type of computer rotations it is possible to lose an axis of rotation. i.e.: you can rotate around say X and Y but not Z. What happens is the object ends up aligned such that further rotations are about the same axis as before. One way to solve this problem is to add a dummy/null object as a parent of the object being rotated. Then you can rotate both the object and the dummy to get the desired orientation.

Inverse Kinematics
See Also "Forward Kinematics"
Inverse kinematics, or IK, is a way to animate a hierarchy, or chain of objects, such that each link in the chain is automatically rotated such that a lower segment is at a specific position or orientation. For example, with an IK leg setup, an animator would position a foot. The legs would automatically bend to accomodate the position of the foot. As the characters main body moves, the IK chain (in this case the legs) would rotate properly so the end chain, or foot stays locked. This is one use of IK. Some animators prefer to use IK for the upper body such as spine or arms as well.

Model
In 3D computer animation a model is an object represented inside of the computer. Essentially it is a virtual object than can be colored, textured and animated.

Motion Capture
Motion capture (mocap) in computer graphics is a way to digitally record position and motion information from the real world. A real actor can move and that motion can be used inside of 3D animation software.

It is similar in idea to the rotoscope, a machine which projects a live actor on film to an animation disc. It is a device, patented in the 1920s by the Fleischer brothers, designed to allow animation to be matched to live action. It was later employed to create cheap but very human like animation which is generally reviled by classic animators.

Motion capture is not without controversy, however. The goal of animation is not to create human like motion, but to impart unique personalities to animated characters, to give them the "illusion of life". Both the Rotoscope and motion capture impose human motion on animated characters, which make them seem flat and lifeless in comparison to those animated or hand keyframed by skilled artists. In the case of the Rotoscope, artists trace human motion but interpret it with the model of the animated character. In the case of motion capture, human motion is copied directly to the animated character. The temptation to use this captured motion and call it "animation" has led computer animators practiced in the art of traditional animation to call it "Satan's Rotoscope" (a term attributed to animator Steph Greenberg).

NURBS
See Also "Spline"
This acronym stands for Non-Uniform Rational B-Splines. These are a type of spline where the curve passes close to but not through the control points or knots. They are currently popular for use in spline based modelling and are similar to B-Splines. With these splines, you're dealing with the hull rather than the actual surface. NURBS goes one step further than B-Splines in that you can have different "weights" assigned to the hull-knots, giving you more control over the curves of your splines.

Polygon
See Also "Spline"
In computer graphics models are typically created either with polygons or splines. A polygon is a 2D shape that exists inside of the 3D computer world. These are typically triangles or squares. By creating polygons in specific locations 3D objects are made. For example 6 square polygons can be arranged to create a cube object.

Rendering
Rendering is the creation of images in the computer from the modelling, lighting, texturing and animation information.

Spline
See Also "B-Spline", "NURBS", "Bezier Spline", "Cardinal Spline"
Splines are a way to describe curves with mathematical expressions. In computer graphics splines are used to control motion as well as to create spline surfaces used for models.

Technical Director (TD)
In large animation houses jobs are typically broken down to specialists. Two main jobs are Animator and Technical Director. While the animator deals with movement, the technical director tends to deal with modelling, texturing, lighting, setup and rendering. In some houses the TD's job is further broken down to have people who only model, or light scenes and so on.

Wireframe Preview
See Also "Pencil Test"
3D Computer graphics usually allow the animator to output finished animation frames in a variety of methods. To test the motion of an animation, wireframe previews are usually used. These are low resolution tests where objects in the animation are drawn only by their edges. Typically there is no lighting or shading done. The wireframe preview is faster and more efficient than the final rendering pass. This allows the animator to repeatedly check how an animation looks before commiting to rendering. This is the same principle as pencil tests in traditional animation.


3] Common Computer Acronyms

These are abbreviations people often use when writing E-mail or news postings to save time.

BTW	= By The Way
CG	= Computer Graphics
CGI	= Computer Graphic Imagery
FAQ	= Frequently Asked Questions
IMHO 	= In My Humble Opinion
IMO 	= In My Opinion
LOL     = Laugh Out Loud
MOCAP	= Motion Capture
OT	= Off Topic
ROFL 	= Rolling On Floor Laughing
STOPMO	= Stop Motion (Animation)
:)	= Image of a sideways smiley face

SECTION 5 - Copyright & Disclaimer
The CG-CHAR FAQ is Copyright 1999,2000,2001 Michael B. Comet All Rights Reserved.

No portion of the CG-CHAR FAQ my be duplicated in part or in whole, by any means electronic or otherwise without prior written consent of the author. The CG-CHAR FAQ may not be sold either individually or as part of other material.

Permission is hereby granted for the CG-CHAR FAQ to be distributed via electronic mail, Usenet news and other internet resources so long as no charge is incurred for the actual document itself and it is not modified.

The section titles "Steph Greenberg's Stages of Character Animation" is Copyright 1996 Steph Greenberg All Rights Reserved. That section may not be duplicated in part or in whole without prior consent from the author.

Some information in this FAQ is gathered from the contributors listed at the top of this document, from resources listed in the bibliography and from infomation gained through general postings on the CG-CHAR list.

There is no guarantee regarding any information presented in this document either implicit or implied. The information may not be correct, useful or helpful. The reader accepts all responsibility for actions pertaining to reading this document regardless of consequence.


SECTION 6 - Bibliography
"Animation From Script To Screen", Shamus Culhane, St. Martin's Press,
    New York 1988.

"The Illusion of Life - Disney Animation", Frank Thomas & Ollie 
     Johnston, Hyperion, New York, 1981.

"Principles of Traditional Animation Applied To 3D Computer Animation",
    John Lasseter, ACM Computer Graphics, Volume 21 Number 4, July 1987

END OF CG-CHAR FAQ