29 March, 2010

Gameplay Animation ~Jeff Cooperman

So recently I sent of one of many demo reels to id Software in TX. I wasn't offered the position, but was given some feedback on my reel. He said that there is good material in the reel, however it's not really geared towards games. After hearing that, I realized that he's totally right. My reel is geared towards character animation, but not a lot to do with video games. I decided that the next few shots that I work on for my reel are going to do with game-type animations. I found this post on Jeff Cooperman's BLOG. I'm hoping it will help shed some light on the subject of game type animation. He wrote it as a 5 part post, I'm just going to lay them all out below. Enjoy, and thanks a lot Mr. Cooperman.
Part one: Where did my anticipation go?


Back when I was at Stormfront, in trying to explain the mechanics of gamplay animation to non-animators, we started talking about how the anticipation needs to be removed to make the experience more interactive. What does that mean really, and why is it ok to get rid if it…surely that’s one of those animation principles.

The answer is better shown than told…when you play a game and interact with a character, the act of pressing the button is the anticipation. Adding more frames to the beginning of your animation causes it to lag, making effectively a double anticipation.

Still. What does this mean. Let’s take a jump, for demonstration purposes. If you click on the image above, the large ball represents your thumb. When you press on the button (represented by the ball hitting the seesaw) the character (small ball) instantly reacts upwards. Adding more frames to the small ball would violate the basic physics of the thing, which leads us to the main idea…game animation is primarily about forces at work. Quick timing often means a great force acting upon an object, be it a sword swing, a jump or what have you. Because the force is usually great, the animations need to react appropriately to the force at work. I’ll post some more specific examples of how this plays into posing and timing, and how we can hack our animation principles back into this simple bit of physics at play to gain back control of our keyframes and give the illusion of anticipation.


Part two: Starting with the principles.

first jump

So let’s start with a standard game style jump. It’s essentially cartoony physics in that this character could never jump that high, but, hey, we just have to sell the motion so that it’s convincing. I’m not holding this up as an outstanding animation…more of a sketch of the idea of a jump. We have a little anticipation, popping up to the apex, a bit of overlap in the spine and arms, the hard landing as the character accellerates to the ground, and the settle and recovery.

Based on our seesaw below, this will have to be adapted. The anticipation removed to match the seesaw effect. The problem is, if you’re at a game company and submit this animation, the designers just hack off the first part of it and either blend into it or just pop into it.

Onto the next section.

(The spheres in each of these test cases to illustrate the basic physics behind each move.)


Part three: Who took my keyframes, or functioned over them?

jump B

Here we have our animation stripped of its anticipation. It’s functional. It works. You can blend into it quickly and have it read, but we’ve also lost something in the process and the overall motion feels a bit lackluster. The forward curve of the body into the the straightening of the spine is gone. Now we go from straight to straight. So, timing works, but we’ve lost some of the charm and feel of our motion.


Part four: Take back the keyframes.

jump C

So take the power back animators. Here’s one simple solution. Add a bit of overlap and offsetting to give back the illusion of anticipation. The pelvis is going upwards like shot out of a cannon, but if that much force is applied to the body, then other parts may struggle to catch up. This is the first of many solutions, but by going back and taking ownership of the in betweens, we’re closer to the feel of our first animation, despite the rapid timing.

I’ve added in a physical representation of the button press, and timed it to be the same as the first jump, the one with anticipation. This makes experience of pressing the button act as anticipation, so the reaction doesn’t feel as fast as it is. By adding offsetting and overlap, it loosens the animation up even more.

More on creative in betweening to come…


Part five: Own every frame.


So the crucial part of getting into fast action is to really make those in betweens count. I reworked the initial seesaw animation with the same timing, but added some smear frame through a single frame stretch of the sphere. It doesn’t change the timing of the animation at all, but adds a much different feel to it.

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