Search found 1375 matches

by jimmy d
Mon Oct 07, 2013 9:40 am
Forum: OpenSim
Topic: .mot file in subject_setup_IK.xml
Replies: 2
Views: 367

Re: .mot file in subject_setup_IK.xml

Hi Ursula, The coordinate file contains joint angles that you may have collected or calculated externally from OpenSim. An example would be if you have goniometer data from the knee that you would like to input (along with marker trajectories) into the IK analysis. if you dont have coordinate data y...
by jimmy d
Tue Oct 01, 2013 7:04 pm
Forum: OpenSim
Topic: Trouble with Contact
Replies: 8
Views: 2964

Re: Trouble with Contact

Hi Anne, Sorted that and saw that problem is the meshes themselves. If you attach a force reporter as an analysis in forward dynamics you will see the meshes do exert a force on one another. I increased the stiffness by acouple of zeros and confirmed that this was proportional. Problem will be that ...
by jimmy d
Tue Oct 01, 2013 5:25 pm
Forum: OpenSim
Topic: Net Joint Reaction Forces
Replies: 7
Views: 1470

Re: Net Joint Reaction Forces

Maria,

Sorry about the confusion. You can get the net joint moments by stripping all the muscles off the model and driving it by torque actuators. The ouputs of that can be used as the inputs for the joint reaction analysis.

Hope that helps,
-james
by jimmy d
Tue Oct 01, 2013 11:52 am
Forum: OpenSim
Topic: Models do not move when loading and playing .mot file
Replies: 4
Views: 639

Re: Models do not move when loading and playing .mot file

Hi Yusuke,
It may be an issue with the Grpahics Card. If you adjust the settings to improve performance (over quality) does the issue resolve? Please let us know.

cheers,
-James
by jimmy d
Tue Oct 01, 2013 11:50 am
Forum: OpenSim
Topic: Net Joint Reaction Forces
Replies: 7
Views: 1470

Re: Net Joint Reaction Forces

Maria,
Yes, that is possible. OpenSim has an in-built Inverse Dynamics tool. Below is a link that describes the Inverse Dynamics tool in OpenSim.
http://simtk-confluence.stanford.edu:80 ... e+Dynamics

cheers,
-james
by jimmy d
Tue Oct 01, 2013 11:34 am
Forum: OpenSim
Topic: Trouble with Contact
Replies: 8
Views: 2964

Re: Trouble with Contact

Hi Anne, by the look of it, you have prescribed kinematics in the forward simulation. With this type of analysis the kinematics will always win. Your contacts will interact if you put a constraint on the joint (slider?) and then apply a force to the tibia that moves it vertically. You may also want ...
by jimmy d
Tue Oct 01, 2013 11:12 am
Forum: OpenSim
Topic: subject-specific CT-based model
Replies: 1
Views: 875

Re: subject-specific CT-based model

Maryam,
Yes, It is possible. Presently, we dont have inbuilt capabilities for this functionality. However a number of external researchers have begun developing their own methodology to do this in OpenSIm.
cheers,
-james
by jimmy d
Tue Oct 01, 2013 11:08 am
Forum: OpenSim
Topic: weld constraint and ground reaction forces
Replies: 2
Views: 1019

Re: weld constraint and ground reaction forces

Hi George, It seems that GRF file has been incorrectly determined for OpenSim. The GRF vector and COP have the incorrect coordinate system and units, respectively. You will have to assume that the GRF is equal for both feet and the COP position (under each foot). This is so the external loads can be...
by jimmy d
Tue Oct 01, 2013 9:59 am
Forum: OpenSim
Topic: Joint Reaction Analysis
Replies: 1
Views: 212

Re: Joint Reaction Analysis

Hi Ralph, A description of the Joint reaction analysis can be found here: http://simtk-confluence.stanford.edu:8080/display/OpenSim/Joint+Reactions+Analysis A paper has also been published that may help you understand the calculation and how it can be implemented; http://www.sciencedirect.com/scienc...
by jimmy d
Mon Sep 30, 2013 4:17 pm
Forum: OpenSim
Topic: Video record and play
Replies: 1
Views: 397

Re: Video record and play

Hi Ingrid, I had the same issue on my desktop. Eventually, I figured out it was an issue with my graphics card which was rather old. I turned the settings of the video card from quality to performance. The OpenSim video improved substantially and the recorded video now plays perfectly. Hope that hel...