The convention for moving models for flight simulation visual system is for the origin to be at the CG location for aircraft models. The coordinate system that we use on our "heavy iron" visual system is +y out the nose, +x to the right and +z up. For an industry disertation on the subject there is a paper on the MultiGen site located at: http://www.multigen.com/support/dc_files/wrm.pdf
enjoy Andy Ross wrote: > > Michael Selig wrote: > > I can ask this differently. What sets the height above the runway of > > the hud-ladder target spot (wrt the 3D model view) --- ie the center > > spot? For c310-yasim and c172-larcsim, it's above the runway. For > > UIUC models, it's below the runway (a recent change). > > Where are you placing the coordinate origin of the aircraft? There > was a confusion/unification about this recently, with the consensus > being that the origin should be, by convention, at the front of the > aircraft (either the nose or the firewall, depending on who you ask). > Strictly, the coordinate origin of the aircraft and the 3D model > should be exactly coincident (or as coincident as practical, given > that there are multiple FDMs and a model file that all have to agree). > > If the UIUC models are reporting an altitude of zero while on the > ground, you'll see this effect. The real altitude should be a few > feet -- however high the nose rests off the ground. > > Andy > > -- > Andrew J. Ross NextBus Information Systems > Senior Software Engineer Emeryville, CA > [EMAIL PROTECTED] http://www.nextbus.com > "Men go crazy in conflagrations. They only get better one by one." > - Sting (misquoted) > > _______________________________________________ > Flightgear-devel mailing list > [EMAIL PROTECTED] > http://mail.flightgear.org/mailman/listinfo/flightgear-devel -- Bruce Finney [EMAIL PROTECTED] Auburn, WA _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
