1: JUGGLING WEASELS

I start with a hazy idea. Then comes the math--before a model, before a map, before anything. Math is the bones. Not every detail, but the major features. They must be solid and consistent before I can go on, because they interact. For example, satellites affect tidal drag affects internal heating causes vulcanism affects carbon dioxide affects surface temperature affects water content affects water vapor affects temperature again... on and on. I can't convey the complexity of these feedback loops in words; here's a sketchmap of some of the more obvious factors:

Like I said, juggling weasels.

The checklist to determine whether a world encourages complex civilization is, paradoxically, much shorter:

• A tolerable temperature range (debatable just what that is)
• Some solid ground (may not be vital, but it sure helps)
• Enough air to allow surface liquids and carry rain
• Enough surface water (or other solvent) to generate rain
• Some tectonic activity to keep minerals in circulation
• Tolerable radiation levels, and...
• Enough time.

But not a sophisticated one, exactly. You can do it with simple arithmetic, no higher math and not much physics, either: just extrapolate from the figures in any pocket guide to our own planets. Just be careful: each factor affects so many others. Sudoku in space!

2: NINETY PERCENT PERSPIRATION

Here are a few basics for beginning deities:

1. Orbit and year-length: gravity changes as the square of distance, but orbital periods (months, years) increase only as the 1.5 power of distance (if you only have a basic calculator: cube the distance of your world from its sun, in astronomical units; the square root of that will be your world's year.) Also, if you double the mass of your sun, it'll only speed up your planets by the square root of two.
2. A sun's light output is the fourth power of its mass, so a slightly smaller star is MUCH dimmer. This has serious consequences for little red stars: to be warm, a world must orbit so close it may tidelock, that is, slow its spin til one side always faces the sun and the other's in perpetual night. Bad for biospheres! But don't panic! Read on...
3. Spin and day-length: early in our solar system worlds spun in about 10 hours, but later impacts and tidal drag slowed many. Giant worlds are hard to slow; with smaller ones like Earth, chance impacts are a huge factor. For example, what slowed Venus wasn't tidal drag from the sun; Earth has more drag from sun and moon combined. Something hit Venus. So you have some flexibility. Even Mercury still spins... sorta.
4. Planets spinning much like Earth may develop a three-cell system: hot air rises near the equator, causing rain; it cools and drops around 30 north or south, causing dry winds (where winds blow off the land, a desert will form, though a wide stretch of sea can re-humidify this air). Proceeding poleward, climates get wetter again until 60 degrees north/south; beyond is a polar dry zone of cold falling air. But worlds with faster spins may have more than three convection belts (consider Jupiter's stripes) and slowly turning worlds may have only one.
5. Sunlight also heats a world only as the fourth root! That is, to double the temperature, you need sixteen times the light. Earth is ten times closer to the sun than Titan, and gets 100 times as much light; but its temperature is only about 3 times Titan's (square root of the square root of 100). High noon on Mercury hits 675 degrees Kelvin; but high noon in Death Valley, with just one-sixth the sunlight, can reach 325; if noon lasted weeks, as on Mercury, it'd reach 400 or more. (Only got a hand calculator? Find sunlight compared to Earth; hit square root twice to get approximate warmth compared to Earth). So sunlight matters, but it's not the only factor; a little greenhousing can vastly change the picture, as Venus attests.
6. The mass of your planet equals its diameter cubed (Mars is about half the size of Earth but has about 1/8 the mass: 1/2 cubed), but the surface gravity resembles the diameter (a half-size world has about 0.5 G, etc)--if the density of your world is Earthlike. A bigger or smaller or nonexistent iron core can affect surface gravity just as much as sheer size. Density is why Saturn, Earth, Uranus, Neptune and Venus all have roughly the same surface gravity, and why Jupiter (318 Earth-masses) still has a surface gravity you could survive, if not enjoy...

Now I have some idea what I'm building!

Next I get physical. I find an old globe, razor off its mountains, gesso it thinly (I like the meridians to show through faintly) and start adding relief. It's white on white still--just a spherical abstract sculpture--and the patterns have to please before I'll go on. When I'm sure of the sea level (which can take a while since temperature and glaciation affect it), I paint in lakes and oceans, covering them with gloss varnish. Next, I just stare and spin. The globe, I mean. For months. My unconscious is trying to work out all the tangled feedback loops determining climate. Each region depends on all the others (the "butterfly effect") so this is slow.

Only when I'm pretty confident of the overall pattern do I start coloring the land: red desert, green woods, golden prairie, white snow... more months! Takes me nearly an hour per square inch--not the first time, but after you factor in all the repainting as I correct the system. And it always needs correction.

When the globe's done, photograph it before a black backdrop. Correct the contrast, add atmosphere and stars in low-orbital shots.

Oh, and start drawing a world map--it'll be revised a million times, so get started early.

Here's a piechart I use to track in a glance what's completed in the workflow. I've scrawled the approximate order of tasks as it meanders through the thing. An intelligent person would rearrange it so tasks are in chronological order, but I never have. Instead it's divided by content:

1. SCIENCE: basic facts and numbers; consistency
2. MAPPING: physical model; world map; regional maps
3. TOURS: safe routes; list of features seen; local maps and orbital photos; sketches of scenery, local people, culture; anecdotes, adventures, travel advisories, plausible chronology
4. CREATURES: a chart of all species with thumbnail photos and capsule descriptions leading to full articles on each species with portraits and a range map
5. REFERENCE TOOLS (in center): links and navigation bars; names; a gazetteer listing the location, character and size of every named feature; latitude and longitude; scales for the maps; definitions of special terms.

Back to the computer now! Invent some names--planets are big, so you'd better coin hundreds of them. Try it! Not so easy after the first few dozen, is it? And they'd better sound natural--languages that the critters of this new world could pronounce. Now convert these bare lists of names into dictionary entries and links to (not yet written) regional tours. Add latitudes and longitudes and the scale of each feature--height, depth, area... Tedious! But you need to know your world. Write descriptions of each feature. These will be the bones of your tours soon, so get them right. Any unusual terms need defining? Probably.

Next, sit with the globe and figure out how to divide it into regions to tour. On some worlds you have obvious geological or ecological regions, and the only problem is to choose scenic routes that'll link together into a seamless web. But on some desert worlds and sea-worlds, tours aren't easy: you must design flyways, caravan routes or shipping lanes that cover your globe without killing your tourists!

When you have safe routes, string together the gazetteer entries you wrote until you have a logical narrative sequence describing the ground features along each path. Just an outline now; style and color can wait. Drop in roughs of any orbital photos or maps that you need; and start sketching landscapes where they seem appropriate.

Your world's still empty. Write up a simple evolutionary history--just what sort of place is this? Do you have a sense of who lives here and why? Make a table of creatures, with thumbnail descriptions. As this firms up, you can start drawing portraits. As the info on each species expands, start a page for each one and collect your ideas there. Make a miniature of your world map and clone it into small maps where you can mark the range and origin of each creature. Now write detailed articles on each species, linking them to the table. More portraits? Sure.

About this time, I make a chart of my illustrations and the (multiple) places they might be used; for example, a portrait of a centauroid might be appropriate in the article on its species but also in a couple of regional tours too. When you'll have dozens of pages and illustrations, such a chart really helps. It's just what databases are for, but I've always just used pencil and paper. Chaque a son gout. Here's a sample from Lyr, with the page-names along one axis and illustrations on the other.

Inevitably, all this time, you'll be expanding and revising those tours as you get to know the locals better, and have more illustrations to add... All these tours need regional maps, too--do you have them? Blow up sections of the world map and add details. I save maps in GIF format despite its limited number of colors; JPG format blurs text, and your names need to be clear.

Keep the file sizes down; not everyone has a fast web connection! No image should be over 100K, and half that is better. So compress JPG images as much as possible, and limit GIF colors to 16 at most--it'll cut the file sizes in half.

Rewriting and adding illustrations can go on for months. But when it feels done at last, test all the links...

PART THREE? I DON'T KNOW FROM PART THREE!

So far I've just described techniques and workflow. Craft, not art.

Now comes the issue of style. But that's so subjective it's hard to address. My last big art project was deeply personal--the World Dream Bank and its book offshoot, Dreamtales. I stripped myself naked on that one--dreams, whew! Planetocopia is a reaction, I guess--something lighter, more... deniable? Objective, or at least with a mask of scientific plausibility! But your artistic needs will likely be quite different.

I'm still struggling with this issue of presentation-style--even going back and changing earlier planets. The only advice I have is negative:

1. High-end animation and intense interactivity are expensive and time-consuming to do right, and you can't possibly compete with the slam-bam seductiveness of games or Hollywood. So why even try? On the other hand, they're weak on ideas. There, you CAN compete. A cretin could.
2. Stylistically, obvious is good and humor helps. You're showing complex unfamiliar data. Science fiction writers struggle with this all the time, and their rule of thumb is: the more alien the content, the plainer the style, or you start losing readers...
3. Bad vibes are common now. Good vibes are rare. Economists tell us rarity creates value. Why not stand out?