I'm not an artist and can't do justice to my ideas the way that George Krauter and Stephan Martiniere have with their gorgeous cover art for Sun of Suns and Queen of Candesce. It's precisely because their images are created primarily for aesthetic effect that I decided to make some of my own. I'm using 3d software to visualize what the world of Virga might actually look like. So consider the following to be snapshots taken by an amateur photographer--light on artistic merit, but accurate to the places depicted.
This first snapshot is of one of the largest town wheels you'd encounter in Virga. This is not the city of Rush in Slipstream, whose wheels are smaller. Such a town wheel could be constructed of iron or stronger metals like titanium. It is kept at rotational speed using large jet engines mounted at fixed points (not visible in this image).
Features of note in the picture: this town wheel rotates around a small asteroid. The asteroid is forested, and there are also several small free-floating groves visible in the foreground. There is a fairly large airship (100+ feet in length) cruising past as well. This is not an airship in the earthly sense, of course; in close-ups you'll see that this particular ship is covered in shingles. I'm currently thinking it's a good model for Chaison Fanning's ship The Rook.
There's a few clusters of buildings floating free in the air too. One feature not visible at this distance is the myriad spoke cables that stretch, like a suspension bridge's, throughout the town wheel.
It's day, of course, with some artificial sunlight coming in from the left. That blue you see to the rest of the sky: don't take it for granted. That colour indicates that we're looking in the direction of deep Winter here, because if there were suns out there the sky would be tinted by them.
This second snapshot is a bit sloppy, and I've included it only because it gives some sense of the scale of the city. In the Virga books I've aimed for more of a steampunk feel to the technology and society, but the towers depicted here are in keeping with the level of sophistication this nation would need in order to maintain structures this huge. They're really on the technological cutting edge of Virga culture, and it shows.
Another close-up, this one a tighter shot of the forested asteroid and inner surface of the wheel. You can clearly see some of the city's parks, which are places of great novelty to the people of Virga; they're the only places where you're going to find plants growing under gravity. People come to them to stare at the trees, which look bizarre and squat compared to what they're used to.
And finally, a little teaser. Who do you suppose that is? Her Admiralty garb is a clue, as are her black hair and the rather ruthless twist to her lips.
This picture isn't finished, by any means; I want to show the lady reaching to pluck a flower from a nearby grass-covered clod of earth. She shouldn't be wearing shoes, by the way. Behind her is a small forest--ordinary enough for Virga--but note the colour of the sky. We're nowhere near Winter here, in fact there must be at least several suns in this sky. Perhaps we're not far from Candesce?
The first picture, above, shows a typical small town wheel being visited by two large ships (perhaps passenger cruisers, or freighters). What's most prominent here are the low-gravity decks suspended above the main wheel; these are places where people who've spent too long in freefall can regain their 'land legs,' and those infirm or with chronic osteoporosis (common in Virga) can live in low-g.
This second image, side-on, shows a feature of the town wheels that I've often mentioned but never explained: the yin-yang staircases. Two of them can be seen snaking from the outer rim of the wheel up to the axle. Yin-yang staircases are very simple: they are stairways that start out with a reasonable slope in the heavy part of the wheel, and get gradually steeper as you climb, so that the effort involved remains about constant but you gain more height with each step. By the time you get to the axle, they're vertical.
Missing from these shots is the huge amount of detail that would flood an actual picture of such a place: there'd be outrigger buildings, cargo nets and balls of water floating nearby, smaller vehicles coming and going, and dozens of winged human figures visible surrounding the wheel. When I get the time I fully intend to create some images like that; for now, you can treat these two as very rough sketches.