Level of development (LOD) is a concept with varying definitions and implementations. Core to the concept is that the level of development defines the content and reliability of BIM elements at different stages or milestones. With “content” we mean geometric information, structured data and linked documentation. With reliability we mean for what uses and to what extent the downstream users of the information can trust the accuracy and quality of that content.

The LOD “classes” that we will present will, if correctly used, help you understand the usability and limitations of the modelled elements. And it is not just about the amount of or granularity of information that has gone into a model. It is as much about the quality and trustworthiness of the information that can be extracted from the models.

The LOD Specifications can be used in various ways. You can use them as attachments to contracts and as supplements to BIM Execution plans. As we will see they are also used as references in common standards to describe information management practices.

As a basic premise the LOD specifications acknowledges the different phases for lifecycle BIM, and help specify the needs at every stage. It tries to answer questions like: What are requirements for geometric content and model data for each discipline and each “level”. What is needed for design intent, what is needed for construction collaboration and what is needed for facility management? What information can be carried over between phases and what information needs to be replaced? What links to historic data needs to be kept?