Animating Models in FlightGear using external FDM (native-UDP)

[Theo Hankers]

Hey Guys,

I'm working as an assistant scientist for the Institute of Flight
Guidance of the Technical University of Braunschweig, Germany. We are
using a combination of INS- and GPS-Systems to record and compute flight
data for analysis and visualization. For the latter I found the
Open-Source Flight Simulator FlightGear to be the best software since
the source-code is not hard to understand, and a flight model, driven by
external data already exist.
In order to achieve good results I decided to import Flight Simulator
models (I received the designer's authorization already) into
FlightGear, because the standard airplanes don't really suite our needs
(one focus is put on aerobatics).
The problem I'm dealing with right now is more of a general matter.
In order to import MS Flight Simulator models, you have to select the
mdl file, using xml files for the model and animation definition.
This is where I got into trouble! I successfully managed to import the
model, but the animation doesn't quite work the way I want it to. The
elevator and rudder are moving perfectly (after some position
adjustments), but no matter which airplane I try to import the propeller
and, more important, the ailerons don't move at all.

<animation>
<type>rotate</type>
<object-name>elevator</object-name>
<property>/surface-positions/elevator-pos-norm</property>
<factor>25.0</factor> <!-- fixme -->
</animation>

As you can see, you have to address the object, as it is named in the
.mdl file. This works for many airplanes with "elevator" and "rudder"
(names are case-sensitive). But no matter which name I try, "left_ailer"
(as defined in Microsoft's MDL SDK), aileron, Left_Aileron, l_ailer,
etc...., the
ailerons won't move, and I get the error message object "..." not found.
So my question is, wether you have an idea, or maybe you can tell me how
the different objects in the mdl file are named (maybe by aircraft
animator or FSDS). Is it maybe a problem, that FlightGear can't read
object-names including underscores (_)?

Thanks a lot in advance!

Sincerely

Theo Hankers
Institute for Flight Guidance
Technical University of Braunschweig

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[AJ MacLeod]

Post by Theo Hankers
As you can see, you have to address the object, as it is named in the
.mdl file. This works for many airplanes with "elevator" and "rudder"
(names are case-sensitive). But no matter which name I try, "left_ailer"
(as defined in Microsoft's MDL SDK), aileron, Left_Aileron, l_ailer,
etc...., the
ailerons won't move, and I get the error message object "..." not found.
So my question is, wether you have an idea, or maybe you can tell me how
the different objects in the mdl file are named (maybe by aircraft
animator or FSDS). Is it maybe a problem, that FlightGear can't read
object-names including underscores (_)?

I think it could be a problem with the way the model is being
converted/imported. Personally I'd try converting the .mdl with
threedconvert (in the source/utils/Modeller directory) to AC3D format.

You can then look at the resulting mess^w model in AC3D, Blender etc and see
how many of the objects have come through unscathed - you might well find
that many objects are "broken up" into many parts and need to be merged back
into one object (say an aileron). You can then name these as you like and
not have to guess at what to put into the XML!

Cheers,

AJ


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Get stuff done quickly with pre-integrated technology to make your job easier
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http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642