Center of the Model, Center of CG, Fuselage pivot point

  • Hey all,

    On the TMD, at the top, is the Telemetry block. Being that I 'think' this is the Fuselage, would that 'tmvector3d' be the pivot point from the part (fusealge) which is listed in the TM.log from compiling it?

    Example from Template TMD file:

    // telemetry
    <[tmvector3d][LookAtPosition][ -0.5 0.0 0.2 ]>

    This is my TM.log from compiling the model, the Fuselage part block;

    0.37-tmmodule: <[string8][object][hingedbodygraphics]
    0.37-export: <[string8][Name][Fuselage]>
    0.37-tmmodule: <[string8][RigidBody][Fuselage]>
    0.37-export: <[string8][GeometryList][ Fuselage ]>
    0.37-tmmodule: <[uint32][PositionID][Fuselage.R]>
    0.37-tmmodule: <[uint32][OrientationID][Fuselage.Q]>
    0.37-export: <[tmvector3f][Axis][ -1.0000 0.0000 0.0000 ]>
    0.37-export: <[tmvector3f][Axis][ 0.0000 0.0000 1.0000 ]>
    0.37-export: <[tmvector3f][Axis][ 0.0000 1.0000 0.0000 ]>
    0.37-export: <[tmvector3f][Pivot][ -0.4522 -0.0001 0.0567 ]>
    0.37-tmmodule: <[uint32][AngleID][ServoRightAileron.Position]>
    0.37-tmmodule: >

    I am thinking I would put that in? or am I good to go? Would 0, 0, 0 normally be a close call for the center of Telemetry with slower aircraft?

    • Official Post

    No, the telemetry LookAtPosition is used for the pivoting camera only as far as I know.

    The R0 of the "rigidbody" with the "Name" "Fuselage" is the mass center of the fuselage.
    There are a lot of other rigidbodies too, those are placed at different positions (R0).

    The graphics for a rigidbody object use rigidbodygraphics objects.
    You don't have to put in all the things from the log file, most of it is just meant for partial copy pasting. The graphics for the important parts like wings and trimmable stabilizers, retracting landing gear, pivoting tail gear and stuff like that are all done using rigidbodies and rigidbodygraphics, the axis and pivots there are physical ones (joints: Position and RotationAxis...)

    hingedbodygraphics object only rotate around one axis relative to a rigidbody (you are assigning it three times, only the last Axis parameter is valid during runtime), used for switches, knobs, etc.

    If you read a bit on the tmd file you'll find a lot of these infos in the new wiki, or at least some of the things (not completed yet)…iki/doku.php/aircraft:tmd


  • Many thanks Jan.

    I completely keep forgetting to go to the Wiki and look into the TMD file. Many thanks for the reminder and thanks for the details here.

    This is all totally new to us Flight Simulator X people. Thanks for being patient with us as we learn this entirely new technology.