I think that everyone agrees that one of the biggest things in XCOM is the repetition of the maps.
According to various sources (sorry I don't have links), Jake Solomon VERY much wanted to have randomized maps in the XCOM:EU release but was told that it just wasn't a practical thing (I think I recall seeing somewhere that it was a choice between randomized maps and destructible maps?).
So, apparently in the upcoming XCOM:EW expansion there aren't going to be a million new maps. In XCOM:EU there are between 59 to 68 unique maps (some are slight variations of each other), and the Slingshot DLC adds 3 additional maps that are only available on specific Council Missions. (source http://www.ufopaedia...e=Maps_(EU2012))
Apparently the new expansion will contain 47 new maps (source http://www.ufopaedia...in_DLC_(EU2012)), which doesn't quite double the number of maps, only ~70% more diversity.
I decided to try and dig in a bit to try and understand more about the maps after seeing an earlier post that the maps contain fair bit of the UI actionscript. It got me thinking about what else might be in the map files.
For my initial testing I started out with the "URB_Bar.upk" map. The base install size is 19.6 MB, which is fairly hefty considering that the compressed XComTacticalGame.upk is only ~7MB.
Unsurprisingly the URB_Bar.upk map is compressed. The usual UE Decompressor (from Gildor) decompresses the unreal package without problem. The decompressed package file is 35.0 MB.
I was able to open and the decompressed URB_Bar.upk file in the umodel Unreal model viewer program. The only additional file I seemed to need was the lighting.tfc file.
The URB_Bar.upk file contains copies of all of the art assets used in the map. Everything from buildings to fire hydrants, video game machines to delivery vans. It appears that the art assets for each map are packaged up and included within each map upk, which explains why these files are so large.
This makes the maps very modular (I think that in theory even if you only had 1 map that map would play normally). It also makes it so that new assets could be included in new maps without modifying the rest of the game (the Slingshot DLC in particular has some unique art assets in its maps).
The URB_Bar.upk also contained copies of many of the weapon FX, such as plasma bolts hitting something, as well as some of the psionic special effects. It also contained a copy of all of the perk/ability icons, as well as other UI icons. XMarksTheSpot had reported earlier that the file contains actionscript used to create most of the tactical game UI.
Each map doesn't appear to contain ALL of the various map art assets used, however. The URB_Bar.upk for example did not contain any trees -- there aren't any trees in this map. I suspect that there is a common library of art assets that are available to the map creators at Firaxis. Each map developer pulls the art assets in for each map as it is created. After completion the art assets are all packaged together into the map upk.
This means that some assets will be duplicated across several maps. For instance a particular car may be present in multiple maps -- the car model and animation assets for it exploding would be duplicated in each mapfile.
It is possible to open the decompressed map file in UE Explorer, but there didn't appear to be any decompile-able code for UE Explorer to work with.
Finally, it is possible to use the Unreal Engine extractor to break apart the decompressed mapfile. I did this with the URB_Bar.upk and now have a very large folder full of stuff to try and parse through.
The first thing I'm going to play with is trying to track down how the art assets are placed on the map in order to try and modify their placement.
One issue is going to be distribution of such maps. Since they are highly modular and contain a lot of Firaxis art assets I'd be leery of distributing a full map upk.
Am open to thoughts on any of this...