On Wednesday 15 December 2004 18:22, Vivian Meazza wrote:
> Jon S Berndt wrote:
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:flightgear-devel- [EMAIL PROTECTED] On Behalf
> > Of
> > Sent: 15 December 2004 17:34
> > To: FlightGear developers discussions
> > Subject: Re: [Flightgear-devel] control surface
> > normalization
> >
> > On Wed, 15 Dec 2004 17:21:13 -0000
> >
> >   "Vivian Meazza" <[EMAIL PROTECTED]> wrote:
> > > A quick search revealed that most, if not all, the 3d
> > > models in the current inventory use normalized values for
> > > animating the control surfaces.
> >
> > See, this further raises a red flag for me. How does the 3D
> > model know how far to move the aerosurface? What does the
> > "normalized value" represent? This requires (like the VRP)
> > more communication between the flight modeler and the 3D
> > modeler. Are they both using the same values for the maximum
> > angular range for an aerosruface - that is, the value that
> > "1" represents? There are software limits. There are
> > hardware limits. Which one is being used by the 3D modeler?
> > It seems to me that the sensible thing to do is to simply
> > use the angular value provided by the FDM - the one that is
> > being used to determine the forces and moments. To do
> > otherwise invites errors and confusion, IMHO.
>
> There are several points here.
>
> 1. The fact is that most 3d (I think all, but I haven't
> checked) rightly or wrongly already use normalized values. It
> would be a significant task to change.
>
> 2. I don't think we tell YASim the correct angles to use.
> Therefore the normalized output, factored to produce the
> correct visual angles, is the way to do it right now.
>
> 3. For consistency, and remember that some 3d models are used
> with both YASim and other FDMs, we need normalized values.
>
> 4. It doesn't matter where the conversion is done. If FG is
> the only user of normalized values, it makes sense to do it
> there.
>
> I have no doubt that this point was vigorously debated at some
> point in the past, and for good reasons we are where we are.
> We need to revisit those discussions and revalidate the
> decisions before making any change.
>
> Regards,
>
> Vivian

I think that normalised values for flight-surface values might be 
vital for YASim - we'd probably have to check with Andy Ross.

It seems to me that because YASim generates an aircraft with 
characteristics to match the config, the actual number of 
degrees that a flap, for example, is rotated is irrelevant - all 
it needs to know is the degree of effect to produce for settings 
between nil and full deflection.

Actually getting the animation right is easy if the real 
deflection angles/distances are known.  For example, if full 
flap deflection on an a/c is 35 degrees then a factor of 35 
should be used in the animation.

LeeE

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