It allows direct import using LumenRT import option. This opens a dialog for browsing your disk to find the object you wish to import.

To access this go to Add Misc > Import Object

Import Object - LumenRT Supports various formats include VUE object (*.vob) , Raw format object (*.raw) , Collada format object (*.dae) , FBX format object (*.fbx) , Object Wavefront (*.obj) , 3D Studio export (*.3ds) , ScalableMesh (*.3sm) , MOHID simulation (*.hdf5) and iModels (*.bim ; *ibim) .