I tried to use the “FREE” edition of L3DT and well it is as you know FREE TO TRY… if you want to use any maps you make i suggest buying the indi license. its only like $40 and well worth it to have version 15 because that has a UE4 EXPORT option… and various options NOT in the Standard(FREE)Version.
It is not easy to make a map from the (FREE) version of L3DT work in UE4.