Secondary Action vs. Secondary Motion

I recently saw an animation student’s summary of the Principles of Animation from The Illusion of Life.   Here’s the one for secondary action:

Secondary actions are almost like follow through and overlapping actions.

This is a common misconception that a lot of people make.  But it’s incorrect. Take a look back at The Illusion of LifeFollow Through and Overlapping Action are principle number 5, and Thomas and Johnston fittingly give five distinct types of follow through and overlapping action.  It’s pretty detailed, with lots of written and drawn examples.

Secondary Action is principle number 8.  If Frank and Ollie were so clear about what follow-through and overlapping action are, then why would they create a principle called secondary action that means pretty much the same thing?  Were they so desperate to come up with 12 principles of animation that they decided to do the same one twice?  Is that really a common belief?


I did a quick Google search and found a not-so-helpful website included this definition of Secondary Action in their list of animation principles:  “A secondary action is an action that results directly from another action.”

I guess it is a common belief.  This site goes on to point out that facial animation is usually secondary action to the body movement.  Really?  Is what Frank and Ollie wrote in the Illusion of Life so confusing that this is what people have abstracted from those paragraphs? Because if you read what they wrote, the secondary movement of the fleshy parts of the face were one specific example they detail under Follow Through and Overlapping Action.

I hear variations of this mistake all the time.  I think some have confused secondary motion with secondary action.  They sound similar enough, but they mean totally different things.

Secondary motion is motion that is, well, secondary to a primary motion.  It’s motion that is driven by or reacting to something else.  Secondary motions tend to be passive, reactive, non-volitional movements.

In a walk, the up and down of the body and the movement of the legs and arms are the primary motion.  The subtle recoil on the head, in reaction to the ups and downs, and the overlap on the hands and fingers, are examples of secondary motion.  , So is the bounce and sway of the hair.  A facial expression, which is generated by the direct contractions of facial muscles, is primary motion. The overlap and follow through on the mustache in reaction to those facial expressions are secondary motion.

When we’re talking about secondary motion, we’re in the realm of physics (Newtons laws, elasticity, etc.).  That said, secondary motion is precisely what Thomas and Johnston were discussing under Overlapping Action and Follow Through.

And now, courtesy of The Illusion of Life, this is Secondary Action:

“Often, the one idea being put over in a scene can be fortified by subsidiary actions within the body.  A sad figure wipes a tear as he turns away.  Someone stunned shakes his head as he gets to his feet.  A flustered person puts on his glasses as he regains his composure.  When this extra business supports the main action, it is called a Secondary Action and is always kept subordinate to the primary action.”

I’ve boldfaced the word business because that’s the key word in that paragraph.  It’s a word we don’t use so much now, but it was well understood by animators during the golden age.   Business is something specific the character is doing.

Per Merriam-Webster, here’s the relevant definition of business, among multiple variants:

6 : movement or action (as lighting a cigarette) by an actor intended especially to establish atmosphere, reveal character, or explain a situation —called also stage business

Here’s a very simple shot from The Iron Giant:

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Look at the middle shot.  It’s practically a throw-away, with Annie simply coming over, a touch exasperated, to see what Hogarth is pestering her about.  But look how much more interesting and authentic the shot is for the way she carries the coffee pot, and especially the way the animator used the pot to put her in a wonderful pose when she puts her hand on her chin.  This is subtle, apt, and wonderful.  This simple, unnecessary bit of detail speak volumes about her character.

And another series of shots from a moment later in the film:

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 Here the secondary action is a little more obvious.  Note the way Hogarth pushes the door half open, the way he plays with the phone cord, the way Annie has to dodge the door almost hitting her, the way Hogarth peeks into the breadbox.  Wonderful stuff.

And, frankly, none of it was strictly necessary.  Hogarth had just left his mom at the dinner, and in the next scene she calls him.  If the object was telling the story as cleanly and efficiently as possible, she could have told him she had to work late just before he left the diner.  It would have saved half a dozen shots, and gotten us to the same point.  But the storytelling would have suffered, and both characters would be a little less richly developed.

I detailed much of this a while back, but it seems to bear repeating.  Check out the linked clip of Jack Lemmon in the film The Apartment,  which demonstrates the concept beautifully. All the stuff Lemmon does with the tissue and his head cold are fantastic examples of secondary action. That business serves to deepen the story, to reveal his character, and, perhaps most importantly, it’s interesting to watch.

I once worked on a project where the director really didn’t get the idea of secondary action. Characters said what they meant, and their actions were generally direct and purposeful. When a character had some prop in their hands, it was there because it directly related to the primary purpose of the scene, and was never used to express the character’s personality. Stage business was rare.

Partly this was done because the characters had poorly modeled hands, and we avoided calling attention to that.  But mostly it didn’t seem to be thought of as important, or else there was worry that it would be distracting, or slow down the process of animation.

As a result, the project was less interesting to watch than it could have been.  And not only was it less intriguing to viewers, but it was harder to animate.  There’s a reason actors love to play characters who smoke.  It’s not just that their nicotine fiends, or that it looks cool — it’s because it always gives them something interesting to do with their hands, and opens up a world of possibilities for facial expressions.

Having a character involved in some stage business gives you something around which to organize your animation.  Imagine that you have the task of animating a character being angry.  In this scene, the character is standing in the middle of kitchen, hands empty.  Where do you go with that?  After you’ve animated an classically angry facial expression, and posed the character with balled up fists, what then?

Now imagine that character is doing the dishes. The anger can be expressed in their washing and in their stacking the clean plates.  You can be much less ‘on the nose.’  The character doesn’t need to throw things around or break anything, but now you have almost limitless possibilities to make an interesting, revealing scene tailored to that character and that moment.

Animating a character involved in secondary action is magic.  If done well, not only does it not distract from the primary purpose of the scene, but it enhances and deepens the storytelling.  Look for any excuse to get secondary action into your shots.

13 Responses to “Secondary Action vs. Secondary Motion”

  1. Ivan Says:

    I’m one of those people who still get confused between the secondary action vs. secondary motion. is there any other examples of 2ndary action besides involving limbs or appendages? and to recap: 2ndary motion involves with result of primary action, merely just a physics reaction and 2ndary action is a motivated action AND it “complements” the primary action?

  2. Kevin Says:

    I think you still have some confusion in this question: is there any other examples of 2ndary action besides involving limbs or appendages? However, I think you summarize it well in your final sentence.

    Secondary Action involves the entire character, because it’s an acting choice. When Jack Lemmon in The Apartment clip sneezes, sniffles, wipes his nose, and generally acts sick, that’s all secondary action. It’s stage business.

    Secondary Motion can apply to anything that can show overlap and follow through. Any fleshy part of the body, not just appendages, and piece of clothing or hair, any prop, etc. Heck, if you’re animating a guy on a bronco, the guy’s entire body will have motion secondary to the bronco’s action.

    Now, if the guy on the bucking bronco is playing with his hat while being thrown around, we could talk about the secondary motion of the arm and the hat (follow through/overlap per Newton’s Laws) and about secondary action (acting business in what he’s doing with the hat that shows his personality and enlivens the scene).

  3. Los Says:

    I really like the fact that you’re calling the idea out about secondary action. Like you said, people don’t think about it too much so the scenes don’t have the life that they could’ve. The characters don’t have much motivation and the idea that you’re trying to communicate may not hit as hard as it could’ve if the animator would’ve given the character some actions to make them feel more familiar to the audience. I love your blog man. Keep speeking this truth! haha. I’ll be looking forward to your next posts.

  4. Alejandro Garcia Says:

    I’m glad that you explained this so clearly because I too had been confused about the distinction between follow-through and overlapping action versus secondary action. If I understand correctly, the former is associated with physical motion while the latter has to do with acting.

    A simple (maybe too simple) way to make the distinction is to say that follow-through/overlapping action occur with inanimate objects (e.g., a rag doll falling to the ground) while secondary action occurs with animate objects (e.g., the rag doll coming to live, dusting himself off and checking his hat as he stands back up).

  5. Kevin Says:

    Hey Alejandro! I think that is indeed a bit too simple. Secondary motion also happens to animate objects — like my example of the rodeo rider on a bronco. The rider is definitely animate, but much of his or her motion during the bucking will be secondary motion (as will the horse’s tail and ears, which are also animate elements). However, you’re correct that an inanimate object can ONLY display secondary motion.

  6. Alejandro Garcia Says:

    Thanks Kevin. It’s great that you’ve clarified this topic and in my class today I passed the information onto my students. The course is “Physics of Animation”, which presents a broad variety of physics topics (basic mechanics, biomechanics, fluids, optics, etc.) as they apply to animation. Keep up the good work, I need more material :-)

  7. Dave Blanchette Says:

    It’s pretty easy to get the two similar terms intertwined.
    Thank you for the well-written explanation and clear examples!

  8. César Sáez Says:

    Nice post! as always :)

  9. Andy Holden Says:

    great article kevin, really intresting reading :-D

    I have a question though regarding this:

    would you plan the secondary action as keys inside your major poses or would you do this as another pass once the primary animation is completed?

    I’m assuming the answer is depending on the context of the shot but in interested in hearing how you would use it most efficently.

  10. Kevin Says:

    Sorry for the tardy response, Andy. Animating the secondary action can be done either way, but you should be fully aware of what your secondary action is going to be from the start.

    Those who work with complete poses (usually in stepped mode until late in the process) would likely plan and execute them all together (build it into the keys from the start). But if you know what your secondary action is going to be, and you work in a layered manner, you could probably do some simple secondary action on top of the primary action. In general though, secondary action is still going to involve the entire body, even if it’s subtle, and so you should be incorporating it into your keys from the start, even if you’re working in a layered manner.

  11. Fiona Nunes Says:

    Your article is very useful and rich in exemples I finally understud what secundary action meant. Thanks so much!! I`ve already added this page to my favorites and look forward to learn more from you:)

  12. Secondary Action vs. Secondary Motion - Chronicles of an Animator Says:

    […] article where he talks about the difference between Secondary Action and Secondary Motion. (Click HERE to read […]

  13. alex vaida Says:

    Thanks a bunch for this one, Kevin ! I read the article last year and bookmarked it. I came back to say thank you, I’m animating a monologue piece at AM and I certainly looked for any excuse to get a secondary action in there. It ‘s made all the difference.

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The animation and animation-related musings of Kevin Koch