Definition of Building Information Modeling:

Building Information Modeling (BIM) is the process of taking 3D objects and systems and making a model of the building. We use a program called Navisworks to merge our CAD files into a model. It combines multiple formats of 3D CAD files and make a building model that can use a automated clash detection to find conflicts. We will send our customers a Navisworks document file that they can us the free viewer, known as Navisworks Freedom,
  to let them see the problems that we may need the customer to verify or provide more information to obtain a solution. It is said that 90% of building owners cannot read blueprints, BIM helps solve this problem.