I tweeted this today and I thought it was worth a repost here for all the Facebook and LinkedIn followers…
There are no LODs.
There are only:
Construction Models, and
What does the above statement mean?
Firstly, that if you are going to try and standardise something you need to make it simple and practical. Secondly, the content of a BIM dataset is best described by its current purpose. It won’t always be a Design model. Once it starts to become a Construction Model, the Design Model needs to die or be used only for crude reference. And once it becomes an Operations Model, it may need some extra data added, but it will likely need a lot of Design and Construction junk removed.
Don’t try and make a model that lasts forever, for every purpose, and then attempt to standardise that as a point-in-time deliverable with some ridiculous metrics.
Make the BIM standards simple, practical, and closely tied to the current purpose of the model.
Posts and articles about Level Of Development are so prevalent, and they can tend to be repetitive, or controversial, or somewhat tedious (or is it just me?) But recently I thought of a different way to look at LOD. What if you take the perspective of the individuals or teams who have to deal with a given generation of data? How does that relate to LOD? Here’s one way it could be expressed:
The Client says “We want something that will maybe look a bit like this”
The Architect says “OK, but here is a more realistic and developed idea of the design”
The General Contractor says “Nice design, but here is something that is more coordinated and ‘buildable’
The Trade Contractor says “That was close, but this is how it is actually going to get fabricated and put together”
The Builder Operator says “Let’s take some of those 3D models and as constructed documents, and figure out what is actually going to be useful moving forward”
random image from web, not related to text above 🙂
A new challenge faced by collaborative design teams – how to work concurrently, yet not do the same thing four times?
Consider these comments from Glenn Jowett: “If you look at the process of designing a steel framed building there is the potential for at least four steel frame models to exist within one design team, four models that have been built from scratch by different people within that design team. … The design team should sit down at the start of a project and map out who owns what elements at what stage of the project … The copy monitor tools within Revit are far from perfect, but this seems to be the only option for walls at the moment. … In traditional 2D, drawings would be issued and revisions clouded; in the 3D model revisions can’t be clouded and drawing issues between the design teams are becoming less and less frequent.” via http://revitst.blogspot.in/2013/08/revit-collaboration.html
Checklist: Finally, some great ideas of what to discuss at a pre-project BIM meeting from the same post: “An initial BIM or Revit meeting should take place at the start of every major project, purely from a Revit and collaboration point of view items for discussion should be: · File format for data exchange · How often are files exchanged · Clearly define what the model is to be used for at what stage in the design process · Who models what and when · Who owns what and when does element ownership go from one discipline to another · Level of development (LOD) – what level of model information should I expect to receive at what stage? And does that meet my expectations · How often should clash detection take place · Project coordinates and project north position. It is important that the above items (at least) are discussed before a project really starts to evolve, and the decisions on each item should be documented and set out in a BIM Execution Plan. Collaboration will be much easier to manage if every member of the design team has the same set of core principles to follow from start to finish.”
To the above list, I would add at least the following:
common list of Phases
common set of Worksets (or at least exchange Workset lists)
how many models will a multi-disciplinary consultant firm be providing? One combined? Or multiple?
discuss if any particular Copy/Monitor Revit Categories will be key to the project
I think that every BIM decision, for standards, LOD, deliverables etc will always be project based, and while you can have a preferred company standard and champion it, different requirements will mean it’s all about the BIM Execution Plan. – Cyus
Coordinating amongst just the design teams is cute, but it’s not the real world. – Aaron Maller
when I first started using Revit 3.1, BIM was all about production with a capital P. It seemed that Revit’s development was heavily focused on how to help me do my work faster & better. … Now you’ve got a lot of people online, in articles, and at conferences talking about BIM who haven’t actually delivered a project in BIM, and saying things like “everything has to be modeled down to the hinges otherwise it’s not BIM”. – JeffreyMcGrew
In this equation, x refers to anything else that might accompany a model being offered as a project deliverable. This might include drawings, specifications, napkin sketches, and so on. The LOD Specification addresses ONLY the “model” part of the equation – it does not serve as a guide to complete project deliverables in current work flows.
And: BIM Fix Blog: Developing LOD (Level of Development) LOD should never be seen as the design is complete, or “design sign off”. Just because an element is; e.g. LOD 300, does not mean it will not change. We are in a design and construction environment. Design changes, coordination, rationalisation, value engineering & preferred construction methods, will all influence the element’s size, shape, location, and orientation. Design sign-off will continue to have the traditional design stage mile-stone approvals (e.g. Design Development and Construction Documentation)