- This page is great, but can someone please add how to set these presets by both command line options as well as the .fgfsrc file?
While your curiousity and effort to get involved in FlightGear are admirable, you are probably well-advised to make use of the FlightGear Devel mailing list to discuss such and similar inquiries.
This will also help ensure that you are getting competent and fast help by people who are actively working with the FlightGear source code.
In addition, when asking questions on the wiki about individual wiki pages, it is generally better to post your comments on the article's discussion/talk page, instead of simply posting it on the article's page itself.
I am going to try to answer your questions anway:
The property tree is dynamically built during application initialization (see $FG_SRC/fg_init.h/cxx, much of it simply comes from XML files found in the FlightGear base package (referred to as $FG_ROOT) that are sequentially loaded into the property tree.
One of the very first XML files that is getting processed is to be found at $FG_ROOT/preferences.xml - this files also contains a section named "presets", so this is where some of the presets you are seeing, are coming from. In fact, this is also where you may add additional properties and values.
Most presets are however directly coming from the C++ source code in the aforementioned "fg_init.cxx" file, just search for "presets".
In addition, properties can be set during startup - via command line arguments, such as the --prop:PROPERTY=VALUE parameter.
Like I mentioned before in our previous talk, detailed help about command line arguments that are supported by fgfs can be obtained by running fgfs --help --verbose on the command line.
Please do make sure to actually check out this list of supported parameters. You can redirect this list to a file by appending " > parameters.txt" to the command line (without the quotes).
Note however, that this requires $FG_ROOT (the path to the base package) to be properly set up, or you'll also need to provide an "--fg-root=PATH_TO_BASE_PACKAGE" parameter in order to point fgfs to its base package.
A wiki'fied version of this list (which is however not necessarily up to date!) can be found here: Command_Line_Parameters
The same syntax that is used by command line arguments can also be used in the ~/.fgfsrc files or its equivalent on Windows machines, just by adding one parameter per line.
For additional details, please check out: http://cvs.flightgear.org/viewvc/data/Docs/README.introduction?revision=1.1&view=markup http://cvs.flightgear.org/viewvc/data/Docs/README.logging?revision=1.2&view=markup