Hi Marlies, Thank you for the questions, and they are right on spot. I neglected that the dataset I work with already filters the data, hence naturally, applying an additional filter, whether 6 or 10 Hz, will lead to weird results. So I need to retest this theory of same kinematic-GRF filter frequen...

Hi Marlies, Thank you for the reply and you are partially right. I overlooked the fact that, as the name suggests, "lowpass_cutoff_frequency_for_coordinates" filters the IK result before calculation, not the ID result generate afterwards. When set to -1, OpenSim ID tool is calculating joint moments ...

Hi Marlies, Glad to know I brought up something useful, and I think I have the answer to your question. I also encountered that the ID result (.sto) has different time stamps compared to the IK result (.mot). I always thought that this might occur from the different sampling frequencies in the kinem...

Hi fellow modelers, A little bug spotted in inverse dynamics. If "lowpass_cutoff_frequency_for_coordinates" is set in .xml, all values to be output get filtered, including time. As a result, if the input IK time interval is uneven due to indivisible reciprocal of frequency, e.g. 1/60s or 1/150s, the...

Thank you for the explanation. Yes, that's what caused the slight discrepancy. I guess modelers simply have to keep in mind that, initSystem() must be called after setting new parameters . Otherwise, even if myMuscle.get_certain_muscle_parameter() correctly returns changed values, this parameterizat...

Hi Prof. Uchida, thanks for the reply. Yes, the purpose of this code is purely for testing the peculiar case I triggered. I am aware that initSystem() must be called after modification, and the test with Arnoldetal2010_2Legs_Default_v2.1.osim indeed shows that forces won't change if initSystem() is ...

Hi fellow modelers, I'm scripting in Matlab to set muscle parameters and obtain the according tendon force, and triggered a potential bug when parameters are changed after initSystem() . [I changed the post title as I realized the bug is not in initSystem() itself.] My understanding is that, initSys...