Michael/Ian:
Sorry for the long drought. Family and work.
The "agn" type files are the files in the photoscenery (if added to the phototextures) and in generic landclass files (again, if added to the textures) that tell the sim what autogen to put where in the sim. When you see landclass tiles, they are really a bunch of scenery bgl files that have accompanying autogen files with the same exact name as the texture file they belong to. In other words, if the two names don't match (with the obvious difference being the "variation" part) then there won't be any autogen displayed.
That's the "simple" answer.
The truth is there may be more than one variation of a specific landclass file, so you there may be different "agn" files to go with them as well. This is done so that there is some variety in the scenery when you are flying over it. Basically, if memory serves, you have about 4-5 different versions of a landclass file that has autogen for cities and/or urban areas so that you have some variety in the makeup and placement of some of the buildings and such.
For the "non-urban" type areas, the variety may be quite less with maybe only one or two agn files to go with the respective landclass files.
To edit/look at them, the simplest way is with the SDK's tool. I can't remember the name, but I think it's called the "annotator" or something along those lines. I remember using it to attempt to make a brand new urban area for the Middle Eastern area using some converted FSX models of AGN buildings. Ended up doing something wrong since it turned Cairo into a "power point" presentation with a frame rate drop.
Anyway, as long as you make a backup of the files you should be able to look at them in a separate directory just to keep things simple and safe. I had just copied the files in question to a working folder then placed the "annotator" in there and went from there.
The "coding" is fairly simple. The FS9 annotator is only rectangles or squares. The FSX one is different, but I won't get into that one since I only messed with it a little a LONG time ago.
Things that are annotated in the bgl as "GREEN" are vegitation. Things that are "RED" are autogen buildings. Things that are "BLUE" are library objects or buildings.
With the library stuff, the more "guids" that are listed in the "default.xml" for the area, the more "stuff" that will show (think variety, here), as long as they are listed under a "master" heading.
For autogen buildings, the building generated is dependent on the "footprint" that is used on the image. This is where "scale" is important. A generic autogen tile is 1km x 1km in size (actually, 1.024 meters), so each pixel is, technically, 1m in size. The reason some of the default stuff was 256 x 256 WAY BACK WHEN, is because the scale was about 4 meters/pixel (the "default" scale for the sim, and the most you can "technically" get for photo-scenery).
Why does the 1024 x 1024 work? No idea. I only know it does if you do it correctly.
How does this correlate with autogen? Well, if you look at the annotator you have various tabs you can use to set various variables, but it's still VERY basic. Remember, we're talking something from 2 decades ago. They needed something that could work with the computers of the day, not what could come down the road. The result is only very basic parameters, but still good enough if you know how to work with the agn textures for the buildings and trees.
Here is where the textures for the agn are located, along with their agn file:
"Main Folder"\Scenery\World\texture
There are summer, winter, hard winter, fall, and spring textures. There is another texture which is "lm" in the name, and this is for night and twilight textures for all variations. The names are, for example, 049b2hw1.bmp or 049b2su1.bmp in the names. These are the "hard winter" and "summer" textures for the "049" autogen are in the "B" region (North American and "generic" fill-in when no area-specific files exist in the "hard-coded" regions). I can't remember what the "2" means here, but the "1" means it's the "first" variation. If you look carefully you can see various other variations -- up to 5 total. Each one has a specific "agn" file with specific layout, so there are no two that are alike.
Not exactly "Modern AI" level "randomness" by any means, but for something from 2002-2003 (when it was coded for release) it's actually fairly good for random display and "mix" of scenery.
Now you can see why this would be a "nightmare" to work with to create completely new autogen for a variation or "version" of an era in FS9. I've done what I can, but just for this particular "type" of autogen there are 25 different textures that would need to be worked on and annotated to get "new" layouts for a cityscape.
Sorry if this took too long or if I didn't cover what you may have been asking about, but I picked up a few things trying to do the whole Platinum Wings thing and the autogen was one of those things.
I'll try and expand some more if you want, but there are MANY good bits of info over at FSDeveloper in some of the older forums and resources.
Saludos!
Jorge
Miami, FL
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I added the location to an older BGL project by mistake. My only options are to just leave it there or produce a flatten file and AFCAD, then figure out the landing zone for the arrestor wires.
