I am not sure how to go about this:You can use command line to launch the editor and bake lighting to save GPU resources for GPULightmass, especially video memory.
- Engine/Binaries/Win64/UE4Editor-Cmd.exe "path\to\your\project\yourproject.uproject" -run=resavepackages -buildlighting -allowcommandletrendering -map=/Game/Maps/MyMap.umap
- Remember to replace Content with Game in the umap path
As a ue4 script/tech noobishy, Where d u enter the above? In the output log?