Levels of Development Definition - BIM NEW ZEALAND

 [1]

The following article summarizes Annex C - Levels of Development Definition - [2] of the 2019 New Zealand BIM Manual.

Level of Development (LOD) is a scale used to show the credibility of the content to be included in specific model elements at different times in the model development. The main purpose of LOD, when included in Model Element Building (MEA) schedules and BIM execution plans, is to explain what each design / engineering team member needs to write in their models, at each stage, and to what extent others can rely on them.

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Level of detail is sometimes misinterpreted as a level of detail and not a level of development. However, there are important differences. The LOD is basically the amount of detail contained in a model element. The level of advancement is the degree to which the geometry of an element and associated information is considered - the degree to which members of the design team can rely on information when using the model. Basically, the level of detail can be considered the input to the item, while the level of development is a plausible result.

LOD tags generally include numbers in intervals to give system users flexibility to define intermediate LOD levels. LOD 350 is defined as a higher level of detailed coordination between disciplines - higher than LOD 300 but not as high as LOD 400. Identifying additional LODs can be crucial in some circumstances, especially for contractual reasons - e.g. handing over models from design team to engineering construction.

GRAPHIC MODEL: 3D geometry is just one type of information. The geometric shape and composition can inform project stakeholders about how the building elements occupy the space. As the design progresses, the accuracy of its shape, location, and extent in 3D space become increasingly important, especially for spatial coordination. But as mentioned in this handbook, BIM is not just a model. These graphic models contain different types of information to explain the geometric elements individually, the system and the design as a whole. The extent to which the model should be developed will depend on the project objectives and should be set out in the MEA's timeline.

DOCUMENTATION: This set of information can illustrate how graphic models are built, define, construct, execute, and how they should be used. While most modeling software includes 2D documentation functionality, separate documentation such as asset information, specifications, calculations, and warranties is mandatory. The way these separate documents are related to the graphical model and LOD requirements can be solved in different ways.

NON-GRAPHIC INFORMATION: Resource information such as hyperlinks, formulas, and alphanumeric text can be embedded in geometric features. This information can follow the model as it is shared between project stakeholders. The precisely defined, object-oriented data structure and classification ensure that information is filled, transmitted and delivered in a seamless manner.

Keep in mind that just because one building element goes to a higher level of detail does not mean that other elements should reach the same level of detail. The LOD level should be nominated based on a milestone or project goals. LOD includes geometric and non-geometric information. Assigning a LOD does not prevent a team from advancing to a higher level if this information is confirmed. See the LOD Forum BIM specification for examples of the graphical representation of the different levels of detail.

Sources:

[1] pixabay.com

[2] Annex C Levels of Development Definition NEW ZEALAND BIM HANDBOOK - 2019 THIRD EDITION - BIM ACCELERATION COMMITTE; BUILDING RESEARCH LEVY; MINISTRY OF BUSINESS INNOVATION & MPLOYMENT HIKINA WHAKATUTUKI - THIRD EDITION - New Zealand 2019 - www.biminnz.co.nz; https://www.biminnz.co.nz/nz-bim-handbook