MoCap Model: Only use marker trajectory if marker was visible during measurement

[WGND (David Wagner)]

Hi,

I am using a mocap model to drive the mechanics of a designed exoskeleton.
I have the problem that one essential marker in my mocap sequence becomes visible only after half of the time. The interpolation function is in this case not suitable, because the position of the interpolation result of the marker is not correct. Is it possible to only use the marker trajectory information, if the marker was visible and measured? So that would mean, that the solver doesn't take the marker information of the first half of the sequence into account, but drives my exoskeleton when the relevant marker appears.

I am using this code:
AnyKinDriverMarker MarkerExoskeleton =
{
CType = {Soft,Soft,Soft};
AnyRefFrame &Marker= Main.ModelSetup.C3DFileData.Points.Markers.ExoMarker.PosInterpol;
AnyParamFun &Trajectory = Main.EnvironmentModel.Exoskeleton.Assembly___1.Node1;
};

Thanks!

Regards,
David

[toerholm (Søren Tørholm)]

Hi David,

Yes this is possible, you will need to make an interpolation function which is zero when the marker is invisible and one when the marker is visible. When you have this function you need to use it as a WeightFunction in the maker driver.

To create the weight function you can use the object "AnyFunSquareWaveThreshold "
for an example on how this is done please have a look in the CreateMarkerDriver class.

To apply this function as a weight in the driver you then write e.g.

WeightFun={.&MyWeightFunction};

Hope it helps

Best regards
Søren