Hi all, I am trying to find the specifics on how OpenSim's kinematics analysis tool computes joint angular velocity. I've always assumed that this was achieve via fitting a GVC spline to the joint angle positions, then the spline is differentiated to get the joint angular velocity (and a simple test...

Hi Colin, Thanks for making this framework available, I have found it very interesting and useful. I noticed from you previous publications that you have also included the meniscus in the knee joint model for some work, but the meniscus is not present in the original Lenhart model. I tracked down a ...

Hi Thomas, Hope you are well and staying safe. I was just wondering if there is a way to perform a "tracking" simulation in scone, perhaps as a way of generating an informed initial guess? For example, could I perhaps: 1. use motion capture data to perform inverse kinematics to compute joint angles ...

Hi Nirav, Your approach to increase pelvis_ty is correct -- however, by default, SCONE moves the model so that it touches the ground plane with a specific force. You can disable this behavior by specifying an 'initial_load' of zero in the 'OpenSimModel' section of your .scone scenario: OpenSimModel...

Hi Thomas, I am wondering if there is a way to specify the initial height of the model for a simulation? My goal is to investigate a drop landing task. I have tried using the standing high jump tutorial as a starting point, as I thought it might create a "drop jump" sort of effect so long as the ini...

You may need to realize the system; https://simbody.github.io/simbody-3.6-doxygen/api/classSimTK_1_1MobilizedBody_1_1Custom_1_1Implementation.html#a4ba80865dc2ae89f2b4f96f1d1cca906 Legend, thanks James that would make sense. Based on that info, I believe I need to realizeDynamics() first. I have tr...

Hi all, I am attempting to develop a simple plug in to compute body segment momentum about the centre of mass. I have managed to achieve my first successful build, but the resulting .sto file only has -1.#IND0000000000000000 for every value, suggesting I have made a mistake (I am a complete novice a...

Hi all, I am interested in calculating the angular momentum of a particular segment manually, which requires one to multiply the angular velocity vector by the inertia tensor. From what I have read, the inertia values for any given body within the .osim file are expressed about the body's centre of ...

Hey guys, Are CMC_Point tasks currently possible in either CMC or RRA? The wiki for CMC says "Although there will be additional task types in the future, such as orientation and point tracking, currently only tracking of generalized coordinates (or joints) is supported." However, others on the forum...

Would you please provide a link to Tim's plug-in? Hi Tom, You can find Tim's plug-in (IndAccPI) here: https://simtk.org/frs/?group_id=433. Note that it only works on OpenSim 3.2 (32-bit), but I did the kinematic analysis on OpenSim 3.3 (64-bit) to confirm that the issue still exists in the most cur...