yo pizza.
Well, this post
http://www.mnpp.net/wp/?cat=10 pretty much sorts most of those questions out. But I will just give you the gist.
We use Windows PCs. Jeremy uses Adobe Illustrator and I use Adobe Fireworks. Since I pretty much function as the publisher, the stuff he sends me in Illustrator ends up going into the "master" file in Fireworks. It's relatively easy to convert and touch things up from an Illustrator source.
Everything is hand drawn, but not in the traditional sense of pencil to paper and then scanned in. All of our maps start with a sketch on paper, but that is usually to determine the overall shape of the map. I usually sketch out where certain buildings will be, or objects and I do it with an effort to find a shape that is fun to navigate and play around. Or if I am doing a forts map, I will sketch out both sides in an effort to find a balance while still allowing for a bit of variety so that both sides don't just look like exact mirror copies of one another.
Then we hop on the PC and start working. All artwork (or at least darn close to 99.99% of all artwork) is done in vector. We used to do everything (waaayyyy back in the day) with what is now called Corel Painter. Our levels were basically multiple layers of rastered paint strokes. But when the Worms Armageddon beta patches came out, and we now had the ability to make a map any size we wanted, we realized that our old classic maps, like Titanic and Af1, could be way cooler if they were, well, way bigger. Of course just blowing up a rastered image was not going to cut it. Blurry nastiness. So that was when the ingenious plan was hatched by Jer to just redesign everything from scratch. At the time we had plans to do that with all five of our color maps, but only ended up doing it to 3 of them... And from that point on we got back into making new content, all vectored and fully scalable.
That's when the maps got big, not just in their dimensions, but also their file size. Global Warming's master file still holds the title at being the heaviest hitter weighing in at 11.3 megs, but Derelict has hit a new record of how many polygons used in a map, with well over 10,000.
As far the way the styles mesh it's actually a question that comes up often with Jer and I. He and I actually do have very different styles. To see this obvious difference, compare Scurvy or Tycoon to Air Force 1. He designed Air Force 1 completely on his own and I did those other two on my own. The style differences are obvious.
But when we collaborate on a level, what usually ends up happening is that (mainly due to time constraints on our real life schedules) I will be the one who lays out the whole level, and Jer will end up sending me "stuff" to go in the level (furniture, bits and pieces, like that). When the finished pieces get to me to incorporate into the level, I add my own touches to the objects, integrating them into the current lighting scheme, adjusting colors and lines, until they look basically like one person did the whole thing. On top of that, when we really need to, we can adapt to each others' styles to keep it as uniform as possible.
Sometimes Jer will actually be the map maker, and I will be the one who comes in later to work on the bits and pieces. Squatters is a perfect example of that. That map was his baby from the beginning. The concept, the art, the flow, everything. Then he sent it to me and I went in and tweaked out all the ices textures and stuff to really add to the coldness of the map. We really love the finished product.
Finally, one of our older projects, Global Warming, was especially interesting to work on, because it wasn't just me and Jer, but we also had a third artist, Josh, who was working with us. That map was 3 distinct styles rolled into one. It turned out pretty cool.