How to connect a weight to hand

Main Forum
1

Hi
I am novice in AnyBody, so please excuse me if my question sounds silly. I would like to model the squat while the subject carries a box by hands. For start, I wanted to attach a box to the MoCap_FullBody model. I created a box and defined its weight. I don’t know how to connect the box to the hands.
I could not figure out where the segments are defined in the MoCap_FullBody model to create reference point.
I defined a driver that attaches a RefPoint on box to RFHD marker. However I get an error as follow:

AnyKinEqSimpleDriver RHBoxDriver = {
AnyRevoluteJoint RHBox = {
AnyRefNode &Box = Main.EnvironmentModel.Box.Right;
AnyRefNode &Hand = Main.ModelSetup.C3DFileData.Points.Markers.RFHD ;

  Axis = z;
  Constraints.Reaction.Type={Off,Off,Off,Off,Off};
};
DriverPos = {0}*pi/180;
DriverVel = {0};
Reaction.Type = {Off};

};

ERROR(SCR.PRS17) : C:/U…s/a…i/M…s/M…k/M…l/JointsAndDrivers.any(22) : ‘Hand’ : Reference of class AnyRefNode cannot refer to an object of class AnyFolder

I know that RFHD is a folder. However I don’t know how to connect the marker to the box.
I would appreciate if anyone could help me.

Thank you

2

Hi,

  1. First, it will be better if you can drive the motion of box using your markers.
    In the AnyBody tutorial, there is the chapter called ‘Making Things Move’.
    In the lesson2 of that chapter, there is the explanation regarding how to define makers from C3D file information.
    Especially, you can use ‘AnyKinDriverMarker’ class for your box segment.
    I would recommend you to use at least 4 markers for your box.

  2. If the relative motion between the hand the box is not that big,
    then there is no need for you define the kinematic constraints between your box and hand segments.
    You can define proper ‘AnyReacForce’ object by using an AnyKinLinear and an AnyKinRotational objects between the hand the box segments.

Best regards,
Moonki

3

Thank you Moonki. I used AnyKinLin and AnyKinRot to constrain the relative movement of box with respect to the hand node.
Thanks for your kind guidance.