Try opening from 3D window. It should convert to an object I think. An object is not that useful though, not without anything to snap on to.
AC25, Rhino6/7+Grasshopper, TwinMotion • Mac Pro 6,1 E5-1650v2-3,5GHz/128GB/eGPU:6800XT/11.5.1 • HP Z440 E5-1650v3/256GB/RX6900XT/W10Pro