The Measure of Things

Mar 22nd 2004

From A Short History of Nearly Everything

by Bill Bryson

In a chapter about the early attempts at measuring the Earth, Bryson describes the obsessive technique used by mathematician Richard Norwood in his efforts to determine the length of a degree of arc of the earth’s surface.

‘Starting with his back against the Tower of London, Norwood spent two devoted years marching 208 miles north to York, repeatedly stretching and measuring a length of chain as he went, all the while making the most meticulous adjustments for the rise and fall of the land and the meanderings of the road. The final step was to measure the angle of the Sun at York at the same time of day and on the same day of the year as he had made his first measurement in London. From this, he reasoned he could determine the length of one degree of the Earth’s meridian and thus calculate the distance around the whole. It was an almost ludicrously ambitious undertaking— a mistake of the slightest fraction of a degree would throw the whole thing out by miles— but in fact, as Norwood proudly declaimed, he was accurate to “within a scantling”— or, more precisely, to within about six hundred yards. In metric terms, his figure worked out at 110.72 kilometers per degree of arc.’

Scientists have been using manufactured measurement devices and specific measuring techniques since the earliest days of engineering, and today they use all manner of vastly expensive and hugely impressive devices to determine all sorts of values for objects that we can’t even perceive, never mind take a guess at the measure of.

What form does measurement take in game development? Well, you can be pretty sure that the programmers on your team are measuring quite a lot, determining the amount of time it takes to compute something or the amount of memory used to store something, and all of this generally logged, cross referenced and available to everyone who needs it. Your production guys are also probably making an effort to measure time in man-hours, keep an eye on team size and track the expenditure of the team in hard numbers. Artists are more than likely working within established size conventions for characters/vehicles/agents and (hopefully) keeping a keen eye on the poly-counts and texture measurements of their work.

So what are the designers measuring? How big is one of your levels in game-units? How long does it take you character to land after hitting the jump button? What’s the length of a standard combat encounter? Approximately how long does it take for your heroes to level up in real-time?

The chances are the answer to those questions is ‘uhh…dunno’. There’s nothing absolutely terrible about that (I’m sure a bunch of amazing games have been made with an entire team of otherwise brilliant ‘uhh….dunno’ designers), but I think there is a lot that you can learn about your game and other games if you spend an afternoon with a chinagraph pencil, a stop watch, the tape-measure tool in your level editor and a video camera. Here’s some interesting values to measure.

1. Time

How long do some key things in your game take to happen? This could be anything from your character jump, weapon reload, level load time, mission length, game length, typical time between save-points etc.

2. Distance

What are some of your average distances in your game and are they consistent? Do they follow a deliberate pattern? Are all your four-player multiplayer maps about the same size, are the two teams in a CTF map about the same distance from each others maps, is the choke point directly central? Do you have one vehicle that is unintentionally longer than the rest? Does one of your enemies have a longer melee weapon than you expected? Has anyone been keeping tab of gameplay-critical distances?

3. Density

How often to things happen in your game? How spaced apart are the enemies, the pickups, the resources etc? Is there a consistency or deliberate design to the density of elements in the game?

4. Weight

Looking at your difficulty curve, how are you dealing with the spacing of tough sections? Is the game ‘light’ at one end and overly ‘heavy’ at the other with content and plot, or is it unattractively ‘lumpy’? Do any of your weapons/enemies/abilities feel out of balance with each other? Do players favour one strategy or technique over others where this is not wanted? Is the game overall too ‘heavy’ with difficulty or plot?

5. Mass

Just how much stuff do you have in your game? How long is/will be a play-through? Is there any extraneous mass in the game systems or content? Do the game systems feel unnecessarily bloated? Like a sports-car designer, can you justify every bit of weight on the vehicle? Is there anything that could be trimmed away to make the product fitter?

6. Velocity

How fast does your game move along, in terms of the rate of unlocking/learning abilities/weapons/tools? What about the speed of plot development, the introduction of other elements like characters? How quick do your characters/vehicles/agents move in relation to the game world? Do your players control these velocities or are they determined by you as designers? Is this intentional?

8. Area

Looking at the screen, what are the relationships between this 2D plane and the things that inhabit your world? How does the character/vehicle/gun/agent move in relation to screen-space? What proportion of the screen is filled with UI? How much of the screen is drawing floor and how much sky/ceiling? What is the relationship between the importance of game elements and the amount of real estate they use in the screen? All of these measurements are much easier if you draw on the screen with a chinagraph pencil or a washable marker.

What are you supposed to do with this info? Well you might learn something in the process of measurement, maybe you haven’t been paying attention to the expanding or shrinking nature of one of these values, maybe there’s a value that seemed to make sense a while ago, but that now seems too big/small, maybe you’d never even considered the need to measure or pay attention to a particular value.

You might also use this data to try and tune your game to feel more like other titles you either admire, or which have set important conventions in your genre that you wish to follow. For each value you want to investigate, take two or three games which you feel have nailed that area of design, and measure them using the same method you used to measure your own title. The chances are you find some correlation or convention in the figures between games that feel right in those areas (the two successful games might have the same reload time for the shotgun, the same waiting time to create a low-level unit, or the same amount of screen-space used by the vehicle in a sharp turn). Compare that convention to the value in your game, and try to adjust yours accordingly to bring it in line with the others. If you are lucky, you might find a solution for that nagging problem you were finding hard to solve.