On Wed, 03 Apr 2002 09:32:12 -0800 >> Something is overwriting the xyz offsets in the c172-3d-set.xml or >> maybe it isn't reading that file? Those are defaults from >> somewhere...probably from c172-set.xml.
Andy Ross <[EMAIL PROTECTED]> replied: >YASim _sets_ those offsets based on its own configuration. I think >this is a problem of data ownership -- who "owns" the location of the >cockpit? I argue that it's the FDM, since it's the code responsible >for other issues of aircraft geometry. But then the model wants it >too. I agree. The published geometric and physical properties of the aircraft - necessary for the creation of an aircraft flight model - often includes if not the exact eyepoint of the pilot at least a diagram that allows the flight modeler to deduce it. The flight modeler may also want to place a point mass weight where the pilot "sits", too, so the information is very much critical to the aircraft flight modeler. JSBSim will include the eyepoint of the pilot - as well as ballast to represent the pilot - regardless of whether or not the modeler uses it. I suggest that the FDM be looked to for supplying such a value - at least as a recommendation. Also, be it known that the day is coming when a standard method of describing aircraft via some form of XML specification file is present. It is likely that the coordinate system used for such a standard specification will be one that is already a standard. That is, the aircraft structural frame: X axis increasing out the tail, Y axis increasing out the right side of the aircraft (when looking forward), and the Z axis of course positive upwards to complete the right-handed coordinate frame. The origin would typically be somewhere at the nose or just ahead of the nose of the aircraft, with the X axis either coincident with the centerline or parallel to it but below it (in order that all the Z coordinates would be positive numbers). It would be nice if there was some coherent and stable method of describing aircraft models and how they relate to the aircraft structural frame, if not coincident. Jon _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
