.dae blender export mystery

[Rarach Cattaneo]

Hi, 

Can"t work out this one, have 8 objects selected on a second layer from main as a phys.mesh but blender tells me  nothing selected empty export file created. Have the selection option selected. If I don"t select it  exports 21object whole file. Blender V 2.79

Anyone?  

[Beq Janus]

Are these selected objects meshes? Blender DaE Export can't export non-mesh (things like paths, lights etc). is that layer visible, I don't recall testing this myself but it would make sense that hidden layers are not exported.