Add a comment that `fixed` in generateDecorations means fixed to PhysicalFrame (e.g. mobilized body).
Add a comment that `fixed` in generateDecorations means fixed to PhysicalFrame (e.g. mobilized body).

opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core