FBX Import Light Build Looks Wrong

Hi, I’m trying to import an apartment in unreal but every time i do the “build lighting” look’s like this. The shadows should be much smoother (i think?) i mean the edges of the shadows should be more straight… I don’t know what i am doing wrong, but if anyone can help me would be very helpful for me, Thanks in advance

You can’t put the entire interior as one object, split the walls of each room to a separate object (and then re-pack the UV’s to fill in the space for the lightmap UV’s)
Also, you don’t need the polygons on top that cover the space between the walls.
The ground plane would need a higher resolution lightmap