Google Season of Docs Project Idea List

Create short video tutorials for the most common user tasks and challenges. We created two short videos like this, posted on our YouTube page that have been very popular. A few ideas for new videos:

How to add a Body and a Joint to your model
How to add Geometry to an existing Body
How do you get motion capture data into OpenSim from your experimental capture system?
What are the differences between static optimization and computed muscle control? What are their respective advantages/disadvantages?
How do you use the Residual Reduction Algorithm in your workflow?
How to use Inverse Kinematics tool to track IMU data.

Documentation Needs

Below is a list of the areas where we need additional or improved documentation. Have you found an area where the documentation needs improvement? Send us an email at opensim@stanford.edu or post a comment below.

General GUI and Workflow

Clarify documentation of how to associate marker sets with a model
How do you get motion capture data into OpenSim from your experimental capture system? Include how to import motion data from standard systems (Vicon, Visual 3D, etc.)
Add documentation about how to generate new setup files for tools, especially when performing analysis of non-gait motions
Explanation of the preferences options in the GUI
Clarify that ALL segments need mass in RRA
Clarify that you need torques (even if zero) in External Loads Setup file to run ID, RRA, etc.
Document force set: how to save it, make it, make an XML file you can load automatically w/o specifying forceset manually in GUI. Also, have examples like: 1) a block with 2-3 forces applied to it at various times and points; and also moments applied to it 2) how to deal with the common case of gait data with the standard column labels: ground_force_vx, vy, vz, etc.; namely, how can I take old data (before the ForceSet XML stuff existed) and quickly run a tool that requires a ForceSet XML file, and then quickly reload the correct XML file in the future? I don't want to have to think about this when running old data in new OpenSim versions. 3) What other strengths/advantages are there to the ForceSet functionality? This is not obvious to users, so it'd be great to have this explained to users with examples for each feature. (From Chand John, via Feature Request)
Describe how to calculate COP from (Fx,Fy,Fz), (Tx,Ty,Tz) to make Tx, Tz zero (From Chand John, via Feature Request)
Refer users to texts (preferably free, online) about how to transform points and vectors from one coordinate system to another, with MATLAB code examples; illustrate both 3x3 rotation + 3x1 translation and the homogeneous equivalent 4x4 matrix. (From Chand John, via Feature Request)
Forward: note that you only need *initial* states, i.e., one row of states (pos + vel for all gencoords, a and l^m for all muscles) instead of necessarily time history of states - but you can also input time history (e.g., CMC output, as illustrated in gait2354 example) and fwd will just read or interpolate the one "row" of data it needs to set the initial states of the model; it will not read anything else from the time history file, so it's not like you're specifying a time history of states for it to track (From Chand John, via Feature Request)
How to use PointKinematics Analysis

Model Development and Editing

How are models bodies, joints, etc. defined in the OpenSim model file?
Expanded documentation of joint reference frame definitions and how to edit
Document how to make notepad++ automatically color .osim files when you open them: 1) Settings -> Style Configurator... 2) In leftmost list, click on XML 3) In User-ext box, add osim (underline or boldface this when describing it) 4) Save & Close (From Chand John, via Feature Request)

API and Development

Expanded documentation of how to get started as a developer, with detailed steps and expected outputs for each step in the tug of war example
A theory guide for the API, underlying algorithms, explanation of the dynamics theory underlying OpenSim
More and more accessible API examples
Documentation of the Hunt Crossley Contact Model
"Data Structures in OpenSim" : lists all of the different types of data structures that we want people to use (i.e., OpenSim, Simbody, SimTK, and native C++), and the methods available to manipulate and access them.
Link to the Simbody Doxygen from the OpenSim Doxygen
Create a chapter of the Developers guide devoted to debugging plugins. This could include such information as: - how to attach a Visual Studio project (plugin) to the opensim java executable; - adding breakpoints and stepping through code; - looking at items currently in memory; - detecting memory leaks, etc. (From Tim Dorn, via Feature Request)
Example - creating a custom joint

Other

A compilation of the publications and studies that have used OpenSim.
System Requirements Page
Instructions for using the K-12 module
Fix Equations in Moment Arm Theory Paper
Table of references for models included with the OpenSim distribution (joint definition, muscle geometry, mass, etc. sources)

Ideas for Videos and Short Tutorials (Project Ideas for Google Summer of Docs)

Have an idea for a video or short tutorial? Send us an email at opensim@stanford.edu or post a comment below.

How to add a Body and a Joint to your model
How to add Geometry to an existing Body
How do you get motion capture data into OpenSim from your experimental capture system?
What are the differences between static optimization and computed muscle control? What are their respective advantages/disadvantages?
How do you use the Residual Reduction Algorithm in your workflow?
How to use Inverse Kinematics tool to track IMU data.

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