Re: [Flightgear-devel] tied properties in the context of subscriptions.

[James T. <ja...@fl...>]

> On 2 Jul 2023, at 18:23, Alan Teeder <ajt...@v-...> wrote:
> 
> 2. Tied Properties
> 
> Many, but not all,  JSBsim properties are also tied to Flightgear properties. My guess is that this was done for YASim comparability.  
> 
> Hence we also see /orientation/alpha-deg and /orientation/beta-deg in the Flightgear property tree. 
> 
> When running Flightgear  /orientation/alpha-deg is updated., but/orientation/beta-deg is not . This is probably a bug.
> 
> Unfortunately there does not seem to be documentation showing the tied property mapping.
> 
In general these bugs are trivially fixable from the C++ side, if someone reports them. (So, feel free to do so…)

The idea for the properties outside of /fdm/jsbsim is to allow generic code (eg, an instrument or similar) to work regardless of the FDM. This is an imperfect situation since clearly more advanced / specialised instruments will likely need some parameters which are FDM specific, but many general aviation instruments can work with any FDM, hence the reason for alias-ing all the properties into somewhat standard locations.

Kind regards,
James