They are aligned with MRI axis and field of view.

Dear Kostas, First of all, each kinematics-kinetics data folder should have a state file (within the zipped vproj file as I recall) that has all the coordinate system transformations, e.g. between anatomical, optimized, tibia, femur, robot, optotrak, etc. That state file corresponds to that motion, ...

Dear Kostas, During experimentation of the tibiofemoral joint, the tibia was indeed fixed. Yet, the reporting of joint kinematics is for posterior translation of tibia. See https://simtk.org/plugins/moinmoin/openknee/Infrastructure/ExperimentationMechanics?action=AttachFile&do=get&target=Knee+Coordi...

I did try that, however, in 2.5 files 'fiber' is seen as a synonym for 'mat_axis'. In 3.0 files this is no longer the case. When loading it into FEBio Studio (3.0 files) it shifts into the MRTI part. We are currently using FEBio version 2.9. We also create our models in a scripted fashion, without ...

Dear Marloes, Did you try by defining fiber direction outside the elastic material definition? As <material id="11" name="acl" type="uncoupled prestrain elastic"> <density>1.5e-09</density> <k>73.2</k> <elastic type="trans iso Mooney-Rivlin"> <c1>1.95</c1> <c2>0</c2> <c3>0.0139</c3> <c4>116.22</c4> ...

Simulation feature was a test implementation to be able to run a simple femur-ACL-tibia model at user-desired kinematics boundary conditions. The feature does not permit users to submit their own models. I recommend you to download FEBio (https://febio.org/) on your computer to run simulations with ...

The bending that you see is expected as the ligaments have a ground substance with a small but stabilizing modulus (providing compression and bending stiffness). You can set that ground substance to zero to represent a purely tension only ligament material. Yet, the simulation will likely have conve...

Dear Prasanna, .NII format is for storing images, e.g. MRIs of the knee. They are NOT model files. Open Knee(s) - Generation 1 has meshes as .inp files that can be imported to Abaqus. Nonetheless, all our model files for Generation 1 and Generation 2 (see wiki page "Roadmap") are in FEBio format (.f...

Hi Sebastian,

Can you clarify what you mean by unphysiological bending of LCL and MCL? Are they penetrating the bone surface? If so, this can be resolved by activating contact between these ligaments and bones.

Ahmet

Dear Lefteris, oks001 is NOT the specimen modeled in Open Knee(s) - Generation 1, which is in tf_joint_FEBio_v2.feb. You can get the geometries for Open Knee(s) - Generation 1 in the source code repository, specifically at https://simtk.org/svn/openknee/_gen1/dat/geo/version2geo/ Please note that wh...