Jim Wilson wrote: > After moving the AC3D model origin to where Yasim wants it (at the > nose) the aircraft rotates fine. (Note that it appears the gear still > compresses abit too much as when doing Curt's throw on the breaks at > 40kts test, the nose comes very close to the ground).
Yeah, the nose gear compresses by 2m, which is too far. I got better results by changing to compression="1" in the nose gear definition. But with that change it ends up too stiff, and tends to end up in an undamped oscillatory "bounce" on its nose gear. I need to get per-gear tunable spring constants and damping coefficients working; the automatically generated ones are almost, but not quite, good enough for all cases. > Anyway, what I now remember is this: the camera position as configured > for the chase view is always in relation to the FDM location. And in > the case of Yasim that location is always the nose. Oh, good point. This will create problems for view direction too -- the viewer will expect to rotate around the "center" of the aircraft instead of the nose. But there are other places in the code that make assumptions about the "location" of the aircraft, too, and they have different requirements. The tile rendering and navigation stuff obviously doesn't care about a few tens of meters, but the altitude computation in the HUD (which is different from the "agl" property) does, and it uses aircraft origin as well. Or consider an ILS receiver, which really wants to use the location of the antenna on the 747, not the cockpit, c.g., or center. (I have no idea where this is, but I suspect it's closer to the tail, so that the main gear are what travel down the exact glidepath). Maybe we need separate origin offsets for all of these applications? Actually, wouldn't a sane default for the view code be to *always* pick a center point for the offset? That is, just pick the center of a bounding box computed from the model (or the FDM). This will match more closely to what the user expects in all cases I can think of. That being said, I'd be happy to put this to rest right now by moving the YASim origin for the 747 and A-4. :) 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
