you can import models in sandbox mode, however they will be static, they cannot move or make animations on them,
so it is used mostly for importing new objects into the game, like for example a structure, some small item, a ramp, a cottage, a house, a tool, a stationed vehicle, weapons, walls, stairs, gates, statues, show stage, beach bar, discotheque, party gathering, ruins, castles, new 3D landed dropships, a random frozen imported character like in the image below, etc...
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Select the 'import user mesh' , open folder, select .obj & .fbl file you want to import into the game.
Don't forget to asset all texture to the object you are bringing before finishing.
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