I FINISHED A MODEL IN SKP AND ASSIGNED THE APPROPRIATE MATERIALS AND EVERYTHING I ASLO EDITED IT IN LUMION HAD PLANTS LIGHTS AND CHANGED THE MATERIALS TO LUMIONS MATERIALS AND SAVED IT EVEN HAD ANOTHER COPY DID THIS FOR DAYS AND NO PROBLEM OUT OF NOWHERE WHEN I OPENENED LUMION THE MATERIALS DISAPPEARD BUT RETAINED THE PLANTS AND THE LIGHTS. THE PREVIEW OF THE FILE EVEN SHOWED WHAT THE RENDERED LUMION FILE SHOULD LOOK LIKE WITH ALL THE MATERIALS AND EVERYTHING SO IK IM ON THE RIGHT FILE BUT WHEN I OPENED IT IT DOESNT SHW THE IMPORTED MODEL FROM SKP AND I HAVE TO REIMPORT IT AND WHEN I DO THE THE MATERIALS ARE JUST GONE 
Please stop shouting!