Need help with a mesh issue

Imported fbx from 3d max, but somehow the mesh keep becoming translucent with opaque settings… anyone know why? Some help would be appreciated 8(

the floor of the pool kept showing the underneath layer of the pool…

After I built lighting it became worse… can someone help?

Yes normals are fine. Just checked the FBX. It’s really weird I have no idea what went wrong… I have a feeling it has to do with the light.

Edit: Once I set all mesh to ‘stationary’ lights are fine but lighting doesn’t seem as beautiful. When I set everything to static the shadaow, colour etc goes nuts. Lightmap resolution is set to highest.

I think it was because meshes were too small… (not sure if I’m right) I redid many of the stuffs and enlarged everything but i’m still getting weird rounded shadows… assets are already gigantic sized…