Problems in c3d initial conditions

Main Forum
1

Hi AnyBody Team,

I am able to upload c3d and successfully run Script to Model. But I need your help in removing error.

ERROR(OBJ.MCH.KIN3) : D:/A…Y/C…d/A…2/A…2/A…n/M…y/GaitFullBody.main.any : KinematicStudyForParameterIdentification.InitialConditions : Kinematic analysis failed in time step 0

I am using AMMRV 1.2 and have my own marker set. Please help me in this it is very urgent, As my boss thinks I took a long time (approx 2 months) in learning something in Anybody which I can’t run successfully. Please help.

Thanks

Reg

2

Hi Reg,

First of all the markers on the leg are very far from their real location, you should see that clearly in the model view. This is because you are using the class CreateMarker instead of CreateMarkerTD. The coordinate system of those two classes is diferent. So for all the leg markers you should use CreateMarkerTD.

Then the orientation of the body at initial conditions does not match the orientation of the C3D markers. You have to use the variables PelvisRotZ, PelvisRotY and PelvisRotX to give the correct orientation to the body.

Finaly i noticed that the two C3D markers pRightASI and pLeftASI are exactly on top of each others during the whole movement. This leads to unrealistic pelvis position because its rotation is not defined. You should correct that in order to have a good motion.

Best regards, Sylvain.

3

Hi ANYBODY Team,

Sorry to Bother again, could you please tell me what is this error regarding I have improved the c3d file and all your suggested changes. please help me out.

  1. Kinematics (Operation: Main.Studies.MotionOptimization.Kinematics):
    .0.0) PreOperation (Operation: Main.Studies.MotionOptimization.Kinematics.PreOperation):
    .0.0) InitialConditions (Operation: Main.Studies.MotionOptimization.InitialConditions):
    .0.0) …Design variables have been updated.
    .0.1) …Load time positions have been re-established.
    Failed to resolve kinematic constraints. Newton relaxation too small. (final kin. error = 1.041786E-005)
    Constraint no. 91 above error tolerance 0.000001, error = 0.000002.
    Constraint no. 95 above error tolerance 0.000001, error = 0.000001.
    Constraint no. 98 above error tolerance 0.000001, error = 0.000005.
    Constraint no. 99 above error tolerance 0.000001, error = 0.000010.
    Constraint no. 101 above error tolerance 0.000001, error = 0.000002.
    Constraint no. 102 above error tolerance 0.000001, error = 0.000002.
    Constraint no. 103 above error tolerance 0.000001, error = 0.000002.
    Constraint no. 104 above error tolerance 0.000001, error = 0.000002.
    Constraint no. 134 above error tolerance 0.000001, error = 0.000001.
    ERROR(OBJ.MCH.KIN3) : D:/A…Y/C…d/A…2/A…2/A…n/M…y/GaitFullBody.main.any : MotionOptimization.InitialConditions : Kinematic analysis failed in time step 0

Regards,
rahul

4

Hi Rahul,

I think that several of the markers are not placed good enough on the body, especialy the feet markers, forearm markers and left auricularis marker. Make sure to place the markers at the same spot on the model as they were on the subject during the recording. Even the markers that will be optimized should not be too far from the real position (no more than 10 cm) in order to avoid unrealistic kinematic.

Best regards, Sylvain.