Hi guys,

Lately I've been playing around with ACM on my Linux box.  ACM stands
for Air Combat Maneuvers.  It is a free (src included) flight sim for
Unix/X.  If any of you are interested in looking at this, check out:

    ftp://ftp.netcom.com/pub/ra/rainey/acm/index.html

After playing around with this sim for a while, I have concluded that
it represents a significant amount of work, and is a very worth-while
program.

A while back I proposed that we base our Flight Gear project off of
ACM.  I even put some ACM screen shots up on the flight gear web
page at http://www2.me.umn.edu/~clolson/fgfs

However, eventhough ACM has a lot of interesting things to offer, for
a number of reasons, I am retracting my previous suggestion that we
base our work off of it's source code.

Eric has done some wonderful initial work on many of the basic
building blocks. I think we should forge ahead on our own. I also
think it will be to our advantage (at least initially) to incorperate
strategic pieces of code from ACM and other sources to give ourselves
a jump start. For instance ACM has a pretty decent flight model we
could just slap in with minimal effort. At a later date, as the work
progresses, these pieces could be replaced with new and improved
modules.

Some of the current features of ACM are these are things we could
borrow, or at least look at for a starting point:

  - Freeware -- all source code included.
  - Pretty good flight model that can be tailored to different kinds
    of aircraft / missles / flying things.
  - Sound support (with some pretty descent sound effects).
  - Allows definition of new planes.
  - U.S. Navy Postgraduate School's Distributed Interactive
    Simulation (IEEE DIS, RFC 1278) code integrated
    into it.  This allows multiple ACM servers to talk to each other
    over local subnets.  You can go 2 vs. 2 over a network.
    This also allows you to integrate with other simulation packages that
    use this same standard.  (i.e. a tank simulation, or ATC simulation or
    whatever.)
  - Some serial-port joystick support
  - Currently has a nice rendition of the Hawaiian Islands based on DEM data.
  - Has distance visibility effects (haze).
  - Models springiness of landing gear.
  - Has a very nice HUD display.
  - Has an HSI on the instrument panel.


Features in the upcoming version (due out real soon now):

  - True spheroidal world.
  - Scene descriptions in latitude/longitude/MSL-height coordinates.
  - Automated extracts of scene descriptions from the FAA databases.
  - Support for a non-zero feet MSL surface height.
  - NAVAID support for the features listed above.


ACM has a number of weaknesses:

  - Terrain modeling has room for improvement in the area of hidden surface
    removal and shading.
  - Usability -- no menus and such.
  - Scenery object descriptors are pretty primitive.
  - Code is not structured well for modularity.
  - Currently only supports Unix/X11
  - Saying the representation of the instrument panel is crude would
    be heaping undeserved praise upon said instrument panel.  Although it
    does have an HSI which FS5/6/7/... still lacks.
  - Scenery is pretty scarce.
  - Although it does have a single overcast cloud layer, this is the
    totallity of it's weather modeling.
  - Currently only support X11 for graphics.


Because of these weaknesses, I think we should come up with our own
design, but borrow pieces where it makes sense to do so.