BIM, or Building Informaiton Modeling, is a work methodology that connects different parties in collaborative projects, achieving better interactions between those participating in the project: architects, engineers, construction companies, etc.
BIM projects are virtual mockups of a final product, which are created from smaller parts called “BIM objects”. These can be generic or specific to a manufacturer.
BIM objects virtually reproduce a real product, such as a door, and contain relevant information about it (dimensions, accessories, links to the manufacturer's website or use and maintenance guide.)
There is no law that requires the use of the BIM methodology in all projects, but some institutions require it since it improves the quality of the finished project.
The Spanish Ministry of Development, for example, requires the use of the BIM methodology in public works and entities that are linked to the Ministry.
In Catalonia, the methodology is mandatory in public works that exceed 5.5 million euros.
Some private organisations also require the use of the BIM methodology.