At 4/10/02, you 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
When I am sitting still at the default airport, I get this: Runway_altitude = -.00053 Altitude = -.39 ft (from ls_generic.h) Here's what it looks like: http://amber.aae.uiuc.edu/~m-selig/tmp/beech.gif The hud diamond (target spot) is below the runway by -.39 ft. To help pinpoint code, we have not changed our uiuc_* code nor LaRCsim wrt altitude/gear. The UIUC models are all below the runway, but the other models going through LaRCsim are not below the runway. As for the aircraft coordinate system, we've never done anything with that wrt viewing. As usual, there's the body axes which is our aero reference point and we can place the cg anywhere we want wrt the body axes origin. >-- >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 ************************************************** Prof. Michael S. Selig Dept. of Aero/Astro Engineering University of Illinois at Urbana-Champaign 306 Talbot Laboratory 104 South Wright Street Urbana, IL 61801-2935 (217) 244-5757 (o), (509) 691-1373 (fax) mailto:[EMAIL PROTECTED] http://www.uiuc.edu/ph/www/m-selig http://www.uiuc.edu/ph/www/m-selig/faq.html (FAQ) ************************************************** _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
