Level of Development (LOD) specification in Building Information Modeling or BIM services is used to denote the level of details (like dimensional elements inclusion, material details etc.) of various stages of a BIM modeling or designing process. LOD specification of a construction process provides a clear understanding of BIM professionals or Engineers as to what exactly is needed to be implemented for a particular level. LOD specification has been developed by the American Institute of Architects (AIA) for the AIA G202-2013 Building Information Modeling Protocol Form and it is prepared by using CSI Uniformat 2010 codes.
LOD BIM specification clearly describes the characteristics of all components of 3D BIM models at various development stages for any type of building. Level of Details or LOD can be classified into five categories, they are:
- LOD 100 (Conceptual Design) – In this stage, the building 3D model is developed to represent the information on basic level i.e. volume, height, area, the orientation of any buildings in detail. Thereby, only conceptual energy model creation is possible at this stage. Software requirements: Software’s used to perform BIM modeling using LOD 100 are Autodesk Revit, Vasari, Ecotect, etc.
- LOD 200 (Design Development) – In this level, building information models are represented as generalized system or assemblies. These BIM models are provided specific geometrical figure by implementing approximate sizes, shapes, and quantities. Software requirements: Applicable software’s to perform BIM 3D modeling using LOD 200 are Autodesk Revit, Green Building Studio, 3ds Max, Radiance, Ecotect, etc.
- LOD 300 (Detailed Design and Documentation) – During this stage, coordination models are created by integrating structural and MEP elements and accurate dimensions are applied to the models. These models can be used to perform clash detection and helps the practitioner to get comprehensive design details of any designed buildings. Software requirements: Required software’s to perform BIM 3D modeling using LOD 300 are Autodesk Revit, Green Building Studio, 3ds Max, Radiance, AutoCAD, Simulation CFD, etc.
- LOD 400 (Construction & Fabrication) – In this level, BIM models are created for fabrication and assembly purposes. These models help Engineers to proceed to the next steps i.e. construction or fabrication and also facilitates them to perform construction schedule. Shop drawings and construction documents can be generated from these models. Software requirements: Software’s used for BIM modeling using LOD 400 are Autodesk Revit, etc.
- LOD 500 (Operations and Maintenance) – This stage is regarded as the final stage of a building modeling development process. In this stage, the created 3D building model represents a fully constructed building and is used for operations, maintenance and retrofits. These models are leveraged to analyze building efficiency. It enables Engineers to create as-built drawing from the newly constructed building. Software requirements: Software’s used in BIM modeling using LOD 500 are Autodesk Revit, Green Building Studio, etc.
Advantages of LOD BIM:
- Helps to get ideas of what is to be used in a particular stage of a BIM designing process
- Provides complete understandings of each stage
- Assists to create proper design and planning of each LOD stages
BIM LOD specification has enabled segregation of the whole BIM modeling and design process in various levels. It has helped in distributing the workload and eases the way for Engineers, Modelers and other authorize professionals.