Jon Berndt wrote:
No. No. No. No. There need not be a prior agreement. The 3D modeler usesFWIW _all_ this patch does is allow the specification of a static
location for
the FDM to report aircraft position at in JSBsim. Previously it
was reported
from the current center of gravity.
That's exactly right. Furthermore, if the VRP is set to the empty weight CG
for an aircraft flight model, and the 3D modeler talks with the flight
modeler to communicate where exactly the empty weight CG is (since it is the
flight modeler that will be setting this location based on physical
parameters), then everyone is happy, as well. The VRP code now in JSBSim
simply allows an agreed upon point to be reported to FlightGear - whether
it's the empty weight CG, or the nose tip, or the left wingtip, as long as
it is agreed upon between the 3D modeler and the flight modeler, the
rendition will come out looking right.
whatever origin suits. It appears in many cases that's the nose. I've heard an origin
for some model is at the firewall. I have an EA-6B model (which I can't release... I
haven't permission... :-( ) with the origin at the tip of the tail. The aeromodeler
uses whatever VRP (you prefer the nose and that's fine). The thing that brings them
together is what Jim Wilson referenced:
If the model is already animated (and/or cockipit models positioned) I would recommend using this to reposition the model: http://www.flightgear.org/Docs/fgfs-model-howto.html#repositioning
Now the only thing is someone needs to know the VRP for the FDM and the origin
of the 3D model. With a few calculations, they populate the referenced properties.
There's nothing nefarious about the new code in JSBSim. Nothing that leads to a dead end.
Nefarious, no. Redundant, yes.
The big question seems to be about where the common reference point should be. Think about that one. Think about what each modeler will know. Think about what both will know. Think about whether the common visual reference should be the same (a convention) across all models so it doesn't lead to confusion.
A common reference point is not necessary, nor is it practical in many cases. You cannot
guarantee the 3D modeler will use that common point. Whether or not the 3D modeler uses
that common point, the repositioning in the IG takes place anyway. Since the repositioning
ALWAYS happens, just us it.
-- Russ
Conway's Law: "The structure of a system tends to mirror the
structure of the group producing it."
-- Mel Conway Datamation (1968)_______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
