Re: [Flightgear-devel] c310 origin

[Jon S Berndt]

On Fri, 13 Dec 2002 14:56:39 -0500
 David Megginson <[EMAIL PROTECTED]> wrote:

Jim Wilson writes:

 > Actually, no, well yes this is a good idea.  But I don't think it is
 > necessary.  AFAIK the model rotates correctly already.

If you are rotating the model in the same order as the FDM, then the *orientation* _will_ be correct, yes. However, if you rotate about the nose, the CG will translate. If you rotate about the CG, then you would be correct. The FDMs rotate the aircraft about the CG. You must translate the origin of the vehicle to the current CG and THEN rotate the vehicle in the same order the FDMs do.

Jon

The FDMs give us lon/lat/alt and roll/pitch/hdg. FlightGear then has
to apply transformations to make the model appear in the right place
and with the right orientation. After reading your posting, I'm
trying to remember how, exactly, we do that -- I'm willing to be that
we just rotate the model around the origin by the roll, pitch, and
heading. That means that the view from inside will be wrong as well,
especially in a big plane.

The orientation should be correct, but the placement of the CG would be wrong, as I outlined above.

Jon

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