Monday, December 27, 2010

Adding Weight to Your Game Design Part 1: Squash & Stretch


Weight is a physical and emotional sensation that people feel everyday. And conveying that in a visual way can be incredibly challenging. But it is something animators do all the time, and the principles they use can be applied to game design. In fact, it needs to be, as many of these principles are sacrificed by the animator for the good of playability. Thankfully, since both animators and designers have to juggle multiple disciplines to bring their creations to life, they speak much of the same language. They just use a slightly different alphabet.

This will lay out the 12 principles of animation, and how they are not only used in animation but how they directly relate to game design. Both animators and designers will realize quickly that many of these are unspoken truths, but the benefit comes in knowing that they can now speak to each other on a deeper level. A level that takes animation and design past being purely functional, but now fully functioning towards creating an honest experience. It is how both can add an extra sense of weight and purpose to the game and the characters within it. Many of these fundamentals are inter-connected, and it is through a combination of all of these working together that you will have characters that move with weight and emote with weight. And that is what will stick with players.

“It is important for the animator to be able to study sensation and to feel the force behind sensation, in order to project that sensation.” – Walt Disney

Squash and Stretch

Applied to Animation
This is the most visible expression of weight and the first thing animators learn and love. The easiest way to show this is with a ball bounce. Instead of just having a static circle bounce up and down, to show weight it will stretch as it falls, squash when it lands, and then stretch again as it travels back up. That movement of mass throughout the object visually defines how the body handles its weight.

The classic ball bounce. Notice as it hits, it stretches, then squashes, to give the most contrast.

The classic ball bounce. Notice as it hits, it stretches, then squashes, to give the most contrast.

When applying this to a character, think of a jump. Before they can lift off, they must first compress down, to store all that energy like a spring. Then when they take off, they stretch wide, no different than a ball bounce.

Edward Muybridge illustrates perfectly the squash and stretch in everyday actions

Edward Muybridge illustrates perfectly the squash and stretch in everyday actions

But this is also done in facial animation. If you want to make a scream feel powerful, have the face scrunch up, with the characters eyes closed and brows furled. And even for small moments, you want to feel it, even if you don’t see it as much. Because again, this is how people will perceive how the body handles and distributes its mass. The biggest pitfall of squash and stretch, when used sloppy, is that the object or character will change or lose volume. And that is the most important thing to remember, the overall weight/mass of the object must stay the same when at rest, stretched and squashed. Changing mass means an instant loss in weight.

Applied to Game Design
In game design terms, squash and stretch is essentially contrast. Let the game store up, coil, for what is about to come and after you have done so, let it loose on the player. Make sure when leading in and out of each action, they feel the stretch. Stretch their abilities, stretch their resources, stretch their economic investment. Then let the impact of the squash take over so the player can see just how much weight and mass they have been carrying around. Because without lows, you can't have highs. And vice versa. This contrast is the core of what will not only make the player see the weight, but more importantly, FEEL it. If you can build contrast into every action, no matter how minor, you will be creating a sense of weight in everything the player does. Just remember, that volume can not change. This will give it solidity, no matter how far you push it. This will give whatever you are creating truth. Easiest place to think of this is with guns. If it is a low powered, rapid fire, then the stretch and squash will be minimal. Now think of a gun that allows you to charge the blast. The longer you charge it, the more powerful the blast. You are squashing the power to its limits, so the blast can stretch out into a beautiful ballet of destruction. In both instances, you will instantly feel how much general squash and stretch is needed. But fine tuning them to feel right, beyond just look right is the key. A common tip animators give is that it is easier and faster to push it too far and pull back, then to not go far enough and keep incrementally pushing it up. I’m not saying shoot for the furthest star in the sky, and pull back to the star closest to you. Go into it knowing which star cluster is the one that is probably the best fit, and aim for the furthest star in that cluster. Because as time goes on, things naturally tighten up and get pulled back as you polish your creation.

Now with player controlled characters, this principle is something that is quickly sacrificed, as taking the time to squash means taking the control away from the player for a moment, while they are stuck in place, storing the energy that is about to released. But there is a tactile squash that the player feels when they press the button on their controller or click their mouse. That can be a great step towards making the player feels the squash, even if they can’t see it as much as the animator might like.

Squash and Stretch are the easiest way to quickly add weight to anything you are working on. And because of that, it can also be a favorite trick for people to use and overdo. But as long as you keep the core of the creation truthful, and care first and foremost about the feel of each over the visual, it will always be a solid method towards conveying weight.

1 comment:

Curtis Hewett said...

Have to say, this is an excellent primer on strategies of animation. I work in game design and I will be directing interns here if they don't know about this.