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Understanding arcs

From: 2D Animation Principles

Video: Understanding arcs

So let's start the practical element of this course by dealing with arcs. There we go.

Understanding arcs

So let's start the practical element of this course by dealing with arcs. More or less everything in nature moves in an arc or a curved path. Unless it's moving extremely quickly or unless it's somehow mechanical, like you know moving as a piston in an engine. So this is the classic bouncing ball animation. And before I play it a couple of things to note, you see that I've numbered it off in odd numbers five, seven, nine, 11 and so forth. That's because back in the good old days when we did this sort of thing on paper and pencil, we animated as I already said on twos, on every odd numbered frame.

And the beauty of doing this is that it is so much easier to see and read visually. The overall acceleration and deceleration and arc on the paths of the arcs. So, as you can see here imagine if we had an eight and a ten and a 16 and so forth all throughout this. It would have taken twice as much time to mark that out. And changes, if i had made a change, would have been much more tedious to effect. So I almost have the luxury of going in and adding even numbered ticks if I feel, okay, we should add a 12 down here.

I can certainly go in and do that, of course. But you'll find your process will be much faster if you work on these odd numbers. And it was good enough for the Golden Age of Disney and Looney Toons and all that good stuff. So it's pretty much good enough for us. So, let's play this thing, see what it looks like. There we go. Now, there's no squash or stretch yet. Now, the whole purpose of this section of the course is just to deal with arcs. You will see, of course, the acceleration and deceleration. It accelerates toward the ground and decelerates at the top of the bounce at 25, 47, and 65, which I've marked in red.

So, with that done, let's take a look at the file very quickly in Flash, if you want to follow along in Flash. Now the purpose of this course is not to teach you Flash animation per se. But I did build the assets in Flash. So if you have access to a Flash program, you'll be able to very quickly take a peep through here and make adjustments or changes. If you wanted to see what this looks like on 24 frames per second you could highlight that layer. And go insert classic tween, and there we have the very same animation on 24 frames per second or on ones as we say.

And as you can see it's pretty smooth, but it looks decent either way. But if you do make changes, make them on twos don't make them on ones, I would suggest, at least, when you're starting out. So if you also want to access the image file itself. If you're working in different software I've created a PNG file. So you can play with that, if you want to bring that in as visual reference to Maya or Cinema 4D or Toon Boom or any other program. So I'm going to show you the application of these principles. Inside Flash, I've just done some quick dirty thumbnail as you can see very rough.

Do not worry about the character animation element of this for now. This is simply to show you How we apply the principles of arcs to a physical actor. Now, I've done some rough timing estimates at the bottom, these are very rough. And, just a general outline to get me an idea of the acceleration and deceleration. But it's also in gray. You see where I've roughly sketched in, where I've guessed the arcs will go, how they will move. So what I did was, I took these images and assembled them into a very rough and dirty pose test.

Let's have a look at this. And now, I've also noticed I've moved the timing charts up. As we would have in the traditional method at the top right of the screen or the paper as it would have been. So now, we have this little fellow doing his moves. And he looks pretty decent. And the trick is to make sure that the arcs are going to work. Before we begin drawing in all these intermediate frame or even animating them with a computer rig. Let's have a look at what that looks like. So what I've done is, and I'm going to move this into a color outline so we can see more clearly. I've plotted the point, I've picked a point on the character's wrist right here, and I have plotted it frame by frame.

So I've moved to the next frame, and as you can see, it's roughly around here. Let's go to the next key frame, and there it is here. And the next key frame and so forth and then that gives us an arc path. And as you can see that arc path is extremely smooth that looks very good. There is nothing in there that's really going to catch your eye. So to show you how I did this from scratch let's hide that. I'll make a new layer. Now I stress if you're working in a different software program you should try to find a method or a way to do this.

And if it's a 3D program it probably has you know, automatic arc plotting built in. I don't know every single program out there, so obviously I can't speak for whatever software you're using. If you're using Claymation or you're working in some other medium. Again, it behooves you to find a way to plot your arcs in a way that makes sense. So that said, let's go in, and I'm going to pick the other arm. And I'm going to pick this area here, and I'm going to put him in outline mode so I can see a little more clearly. Let's get the brush tool, let's do this in red.

And on this layer, I'm going to make just one complete empty layer, So let's go to frame one. Again, brush two. So I'm going to make a point on his first right hand and actually move to here. We'll go to the next one. And it's somewhere behind his head, around here. This is number one, this is number 15, and this is number 25. So, as you can see the hand is moving roughly on this path from here to here. And let's go to the next one.

And don't be afraid to go back and forth to make sure that you're brain isn't deceiving you. And let's plot, to there, and the arc continues to move, so it's going here, to there, and then it loops back around. These kind of points here, that's fine, that's a change of trajectory. He follows this path, changes trajectory here, and then, he's moving back, that's going to be fine. And then the next one, number 37. I think, will be somewhere around here. And then we go to the final frame, which is roughly around here.

And so, we have a pretty big change of direction here, so that might be a problem. So let's see what that might feel like. And we might get away with that. What this tells us is that either we should change the position of this hand. But I like that position there, I don't want to change it. So, I think what we should be watching out for is something on the in between frames. Let me delete this path here. And just as long as we make sure that when we draw the frames that lead from 37 into the end pose. That they follow the arc like this.

So this is essentially how we plot points Arms and you can apply it to feet, legs, the head any part of the body that you think is catching your eye it's doing something weird. It's very, very hard to see these things exactly when you play them at frame rate. And when you plot them as arcs like this it is so much easier. Suddenly you go that's what's been catching my eye. Well this method that you use. Well do a little bit of housekeeping arcs hand his right hand arcs hand right.

It's actually his physical left hand. So that's it. That's the method that you use. At least in Flash. And certainly, keep an eye out in whatever program or software or technique that you're using to make sure your arcs are as clean as this.

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This video is part of

Image for 2D Animation Principles
2D Animation Principles

35 video lessons · 6905 viewers

Dermot O' Connor
Author

 
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  1. 1m 42s
    1. Welcome
      51s
    2. Using the exercise files
      51s
  2. 18m 9s
    1. Understanding appeal and design
      4m 3s
    2. Comparing body types
      6m 27s
    3. Understanding silhouette
      1m 52s
    4. Creating gesture drawings
      2m 50s
    5. Tying down the drawing
      2m 57s
  3. 18m 10s
    1. Comparing storyboard styles
      5m 8s
    2. Understanding shot composition
      4m 36s
    3. Demonstrating lighting
      4m 8s
    4. Understanding the 180-degree line
      4m 18s
  4. 13m 8s
    1. Understanding X-sheets (dope sheets)
      3m 25s
    2. Comparing frame rates
      4m 39s
    3. Creating sweatbox notes and preparation
      5m 4s
  5. 18m 42s
    1. Understanding arcs
      7m 38s
    2. Squash, stretch, and volume
      4m 59s
    3. Comparing timing and spacing
      6m 5s
  6. 10m 4s
    1. Using anticipation, overshoot, and settle
      4m 2s
    2. Breaking and loosening joints
      2m 43s
    3. Leading action
      3m 19s
  7. 19m 51s
    1. Understanding primary and secondary action
      4m 14s
    2. Using overlap and follow-through
      6m 0s
    3. Applying lines of action, reversals, and S-curves
      4m 34s
    4. Moving holds and idles
      5m 3s
  8. 15m 52s
    1. Understanding walk and run cycles
      5m 24s
    2. Creating eccentric walks
      6m 50s
    3. Animal locomotion
      3m 38s
  9. 14m 31s
    1. Finding dialogue accents
      2m 42s
    2. Creating dialogue through body movement
      2m 46s
    3. Creating stock mouth shapes
      5m 4s
    4. Using complementary shapes
      3m 59s
  10. 13m 8s
    1. Creating thumbnails
      4m 31s
    2. Comparing straight-ahead and pose-to-pose animation
      4m 37s
    3. Adding breakdowns for looseness
      4m 0s
  11. 2m 9s
    1. Next steps
      2m 9s

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