--- Jon S Berndt <[EMAIL PROTECTED]> wrote: > On Fri, 13 Dec 2002 13:45:11 -0500 > David Megginson <[EMAIL PROTECTED]> wrote: > > >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 > > Isn't this the way it used to work? Or, how does it work, > now? I think we track the initial CG, as well as the > current CG. > > >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? > > Of course, the best way *is* to use the same origin for > the FDM and the 3D model. If we all agree on an "FDM > Frame", then we'll all know where the CG is if we report > that number based on the FDM frame (and by FDM frame I > mean the nose-tip thing we've been talking about). Euler > angles from the FDM should be able to be used directly by > the model rendering code I would think, instead of having > to do rotations *and* translations for the 3D model if we > have different frames of reference.
I think it's pretty clear that we aren't going to agree on one coordinate system to use. Aside from that, agreeing on one takes away the freedom to choose a location that makes sense for the aircraft you are working on (for both the FDM and 3D modeling). > > Jon > > _______________________________________________ > Flightgear-devel mailing list > [EMAIL PROTECTED] > http://mail.flightgear.org/mailman/listinfo/flightgear-devel > > __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
