Check that any component of the marker location is blank, and if so its value will be NaN.
Check that any component of the marker location is blank, and if so its value will be NaN.

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