Monday, 21 November 2011

MC 21: The Pendulum

I had a body mechanics piece planned for this challenge, but its on hold till after xmas. Instead, this fortnight's challenge is written by Cosmicfool. Hoping it helps people who maybe struggling to find a good way to build a pendulum. Those who are familiar with this exercise, may have the freedom to be creative.
Hope you all enjoy!
Hey, this is another back to the basics challenge. As I was preparing this pendulum exercise, and talking to other animators. I was shocked to discover almost everyone I talked with had never done one before. You all know who you are. Now is your time to do one. Perhaps you'll learn a thing or two.

So the idea behind this challenge, is to take the pendulum and move it across the screen however you decide. Have each piece underneath it follow through, drag, and swing accordingly. You will be amazed at how many different ways you can do this, and how many ways this can apply to your animation! When we were brainstorming different things it could be, the list went on and on. A man on a zip line. A person carrying a bag of groceries. In harmony with last challenge it could be a man swinging on those rope things at a circus.Use your own imagination and think of ways you can apply this animation to really spice it up. I can promise all who participate will benefit in their animation from this one.So for those of you that are just learning animation, here's a loose step by step guide that I took to make this example piece. Hope it helps you out.

Step 1: Establishing your timing, and moving the board from point a to b.
Here I will show you how to use a timing chart to build a base for your pendulum. I have gone on to make changes afterwards, but it will give you a good result and a nice foundation to build upon.

So working in the front view, I'm going to move the board in translate x from a to b. First thing I do is I plan out my timing. I need an anticipation. I need to move across the screen. I need to ease in and to ease out of my movement.
  • To start, I set a key on frame 1.
  • I don't want my animation to start moving yet, I wish to allow the eye has a chance to see the screen. Therefore, I start my animation on frame 9.
  • I have a 7 frame anticipation to frame 16.
  • I have decided it will take twenty five frames to move across the screen, finishing at frame 41.
So as it sits, I have a key on 1, the same key on 9, my anticipation extreme on 16, my moving extreme on 41. I now need to really refine this movement, so I get a nice feel. To do this all my curves are in linear.

Placing first few keys: Click to enlarge
Timing chart
What I'm now going to work on is my spacing. To control my anticipation I added a key on frame 9 and basically pulled it up a bit, so I didn't move to fast when my movement starts. I found that was enough to give my anticipation a good feel.For my forward movement I used a timing chart that I'll show and explain.
Now the forward movement begins at frame 16. But for now, let's imagine it had started at frame 1. Here's the chart:

So here's how you read this chart:
(please note, 1 in this case represents Frame 16 on our pendulum)

1 is our point of origin.  Frame 13 is our middle point. Frame 25 is our end point.

We need to separate the animation into two halves. We want to focus on getting from frame 1 to 13. We shall call this Part A. Part B will be from frame 13 to 25

Part A
Frame number:                             1   --      9     --  11    --    12    --   13   
Percentage from frame 1 to 13:     0%       25%     50%       75%      100%

Part B
Frame number:                             13   --   14    --  15    --   17    --    25   
Percentage from frame 13 to 25:   0%       25%     50%       75%      100%

So if you are looking at this you will think, 1-11 and 15-25 frames only accounts for 50% of the entire movement. Yup. They are creating my ease ins and outs. 9-11 is my acceleration. 15-17 is my starting to slow down

Now here's how I implement this chart using the graph editor (you could use the dope sheet also, but I like using the graph editor as I can polish my curves while I'm here).
  • Basically 1 is when I start moving forward from my anticipation. 25 is when I reach my end point.
  • At frame 13 I am half way through. If I was in linear, at frame 13 I would be half way through my movement. So I key frame 13. Up till this point I just had a key on 1 and 25.
  • Now I key frame 7 and 4. I know frame 7 is halfway from 1 and 13. Based on my chart, I want this key at 11.
  • I keyed 4 as well which I knew was the quarter way point. Based on my chart I wanted this key on frame 9.
  • So now the first half is correct. I than did the same on the back half of the movement. Frame 19 I moved to 15, and frame 22 I moved to 17. 

Graph of timing chart
Once the timing chart has been transferred to the graph editor, it should look like the pic. Next, I merely polished up my handles. I also noticed I ended a bit faster then I wanted to, so I moved my last key over about 7 frames, to have a really subtle slow stop.

Step 2: Rotations 

I needed a rotation on the big board to sell the anticipation. I needed one to show I was going to accelerate. I needed one to show I was going to stop.

I also needed a couple little subtle rotations at the end, to show the movement was coming to a halt. If you ever watch a car come to a stop at a light, you'll notice the body comes up and then down. The harder the stop, the bigger the recoil.

So heres I how I worked it all out: My body starts coming backwards at 9. So I decided to start the rotations at 10. My body starts accelerating at frame 16, so I figured to have the backwards rotation stop at 17, just so they didnt all settle same time. My biggest movements in forward progression was 26-30 so I decided to have it come its extreme at 31. At frame 35 my movement was starting its biggest slow down, so I decided to have its next extreme to show it was stopping hit at that frame. Then I just threw in a few keys to sell the stopping motion.

Platform graph: Click to enlarge

There really wasnt much to my breakdowns here, you can see in the graph the only ones of significance were when the board starts really accelerating, I just wanted to have it almost hit its extreme before the fast movement started, and than to slow into its big extreme. You'll see a few keys outside of that, but they are merely to prevent the board from being straight.Usually if I'm going to be passing the 0 point in rotations, to avoid things being straight and boring, I'll add a key before and after it, just so there is no boring pose in the movement.

Step 3: Now the fun part. Animating all those little guys underneath

So here's the fun part. This is where you really have a lot of room to play. How heavy do you want the chain to be? You can really start playing with the shapes you want that chain to make. If you look at my clip, my major poses were on frame 16, 24, 26, 36, and 41. The rest was just causing it to settle.

Frame 16
Frame 24
For frame 16, that was when my board hit its anticipation extreme. I wanted this pose to show that chain had some weight, so whatever it was pulling was resisting the momentum of the board. What was important here, was to get this pose, but not have the bottom of the chain pop. If that bottom of the ball rotates forward from its sitting pose, I have made a mistake.
Frame 24, I was still trying to maintain that same shape as 16, but show the momentum of the board going backward had started to effect that bottom chain.

Frame 26
Frame 36
Frame 26 is my reversal, and at this point, the board and momentum is winning, and that chain is gonna start following it. 36, is when that upper board really shows its slammed on the breaks, so I wanted to hit my biggest extreme here of the momentum of that chain coming through here. 

Frame 41
Frame 41 is when that upper joint hits its first extreme of settling. So I really wanted that bottom joint to be at a nice contrast to it, and hold it back to show it was gonna get whipped by that upper joint that was being whipped by the board above it.

Basically the rest is just settling that weight. Here is the final graph and animation of my pendulum.

Final graph editor for translates and rotations

Its only a simple pendulum, but I hope it gives you something to build upon. Be creative and see what you can come up with. Good luck and happy animating!

Again the animation could be anywhere between 75-125 frames. If you have any questions about submission requirements, please check How-to-participate section for more details.

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