My model's mesh is deficient in Unity.

I meed a model of a temlpe in Maya, and in Sketchup Pro too, but if I import one of the FBX, the mesh is deficient. Like the wall, floor or something randomly disapears.

Maybe if you create the walls and floors as seperate meshes and then use joints to combine them. You’d probably get much more flexibility in terms of what you can do if you do this as well.

it consists of 1 mesh. I used Sketchup last time, the models was combined into 1, and after the inport, the floor disapeared. but only in Unity