Open Source Foot Orthosis Design Software

I'm looking for open source foot orthosis design software. I am familiar with Meshmixer, Fusion 360, Blender, Rhinoceros, etc., but would like to find a plugin, or new open source software that works well in the foot orthosis arena. I am also familiar with one plugin that works with Rhinoceros. There are many proprietary programs out there, but most are relatively expensive and are often limited to their proprietary system. As far as I can tell, Autodesk does not have a new version of the old Delcam OrthoModel in the works; hence my interest in other possibilities. Thanks for your replies.