import a 3d max file

hi every one
I want to import a building in unity.but I have a problem with collider.when i use a camera .camera have no collision with wall???what am i doing???

Cameras have no colliders. Unless you are using a First person controller of some sort. If you just have some script attached to a camera to move around you will always go through walls. Also, FBX (which is what unity uses to import models from programs like max/maya/ext) does not import with colliders, you have to build your own colliders, generate a collider mesh in max and use that as a collider or have Unity generate collisions based on the mesh which is very cpu intensive.

Thanks for your answer.i have a building that have many detail.how i give collider all of this???and how i can change my scene in unity?/i want to seprate my project to 3 scence.

and can I make a button that show a special place in my building when user click it???