Body falling through the ground

[Carlo Rasetto]

I am having a problem with the simulation. I load a model (gait2392_simbody.osim) and a motion, but when I start the simulation the body does not move but simply falls through the ground, what can I do? I have already tried deleting and re-downloading the program and also downloading it on another PC, but the problem continues occurs. I am using OpenSim 4.5.
Thanks for your time and help, Carlo Rasetto

[Madeline Grosklos]

Hi Carlo,

I think more details would be helpful. What is the source of your motion file?

Also, does this happen when you load the example Gait2392 model and motion provided in the OpenSim download?

-Maddie

[Carlo Rasetto]

Hi Maddie,
I am using only the motions that are given when downloading OpenSim as I have to complete an assignament based on those. I submit an attachment as to show you what is the problem and what models and motions I am using.
Thank You for the help and time, Carlo

https://drive.google.com/file/d/1ns9jvO ... drive_link

[Jon Stingel]

Hi Carlo,

Unfortunately, the drive link requires you to provide access, so we are unable to see the files.

It sounds like perhaps you are trying to perform a forward dynamics simulation using the tool in the GUI. If that is the case, here are a few thoughts:

• The gait2392_simbody.osim model does not have any contact surfaces in it by default, and so without any other information it would make sense that it falls due to gravity

• You can supply a set of external loads, such as ground reaction forces, that would support the model (and therefore not require contact surfaces)

• Here is a good resource for exploring the forward dynamics tool: https://opensimconfluence.atlassian.net ... d+Dynamics

Hope this helps!
Jon