Prevent Gameobject/Camera from penetrating another gameobject/mesh

Is there a way to prevent a Camera from penetrating through another object?

I have camera in a scene that has a modified Mouse Orbit Script[default with unity] but using the arrow keys for navigation. It also has a Gameobject [orbit origin] which can be used for forward and backward movement.

The only problem is that I want to put a script or component that prevents them from penetrating other objects in the scene, especially the building[mesh].