Vertical Wall Detection

Hello! 

I am currently building an application in Unity in which users throw objects into their environment to lure an AI to them. The problem I am having is that collision is a major part of this. I used the Vuforia Ground Plane example scene as a jumping off point to place a collision box on the floor to allow dynamic objects to land and bounce on the floor. I would like to achieve this same effect for the walls of the room, as well. Is there any way to achieve this same vertical plane detection without the use of markers?

Thank you!