When exporting the model as FBX, there is an option in the dialog to include Cameras and Markers.
Even if Markers is checked, not all markers are exported. It seems to be exporting only the ones with at least one projection? My markers come from an external source, so I have the 3D position in the scene, but I do not have a projection at that time, is there a way to include these markers in the FBX file ? (I'm using markers to store the position of the lights)