David Megginson <[EMAIL PROTECTED]> said:
> OK, everyone, here's the problem. I tested watching the PA28-161 from a
> fixed point on the ground, and it does, in fact pivot around its nose still.
Maybe not. Your cvs log shows that you did not make the target offset
correction for the tower views only the view n=1 chase view. See the p51d config.
> The problem is that the model code gets the roll/pitch/yaw from the FDM and
> then applies it to the 0,0,0 point in the 3D model, which happens to be the
> tip of the spinner for the Warrior (as it is in the weight-and-balance
> section of the POH). YASim isn't doing anything wrong; the model code just
> doesn't know where the aerodynamic centre of the model is, so it doesn't
> know what point to rotate the plane around.
>
> With Jim's suggested patch, the camera rotates with the plane in the chase
> views, so it *looks* like the plane is rotating in the right place, but it
> is not.
Well the patch is necessary always. Unless the origins are defined at the
aerodynamic center (an ambiguous location).
> So, given that the aerodynamic centre of an aircraft can shift based on
> loading and flight conditions, how can we report that from the FDM back to
> the 3D model code? Is this something people worked out in a previous
> thread? I'm assuming that the 3D model and the FDM config file are using
> the same reference datum for coordinates.
Ah ok. Sorry folks. This is _a_ problem:
<fuselage ax="0.5" ay="0" az="0" bx="-7.75" by="0" bz="0"
width="1.5" taper="0.2" midpoint="0.3"/>
To make this work both the FDM origin (where lon/lat/alt are reported at) and
the 0,0,0 origin of the 3D model should be the nose. If you do that, then
all will be fine. In this case you've got the origin a half meter back in the
FDM and the 3D model is 0,0,0 at tip of nose cone. Visually the error is
probably "barely" noticable.
Please keep this simple. It is exactly as it needs to be. FWIW I fought Andy
on this issue (didn't believe him either) a while back. Then all of a sudden
a light came on and I got it.
Best,
Jim
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