David Megginson <[EMAIL PROTECTED]> said: > Jim Wilson writes: > > > 2). On a fixed wing aircraft, if origin is anywhere but between the > > wings the external model views that follow along with the aircraft > > (e.g. chase view) will not look correct. The camera is tied to the > > origin. If the origin is at the nose or tail then the plane > > "looks" like it's wagging when it pitches. And if the origin is > > too high or too low again the model can "appear" to be swinging > > like a pendulum or sliding when it should simply be rolling. > > OK, finally I understand the problem. What we need to do, then, is > apply the euler angles to the CG rather than the origin when rotating > the 3D model. We need only two steps: > > 1. have the FDMs report the current CG relative to the origin (if they > don't already); and > > 2. add a couple of transforms to acmodel.cxx so that we use the CG as > the centre of rotation. > > This will be especially nice for modelling out-of-balance situations > (like 500lb of baggage in the back of a 172) -- everything will come > out looking right. It will also be valuable for aircraft that have > massive balance shifts, like a military aircraft dropping ordnance. I > don't expect that this will be a big job. What does everyone else > think?
Actually, no, well yes this is a good idea. But I don't think it is necessary. AFAIK the model rotates correctly already. But with the camera tied to the origin as it is in the chase views, you can get the "appearance" that the model is not rotating correctly. You could tie the camera to the CG offset, but really I don't think it will be noticable for the added effort and math. (The only time it might be noticable is when flying in formation otherwise the background is too far off). It is much easier to just put the origin itself somewhere near where the aircraft would seem to pivot and roll about (approx cg, normally balanced) and leave it at that. The 747 looks fine since Andy made that very change to it a couple weeks ago. Best, Jim _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
