BIMForum LOD Specification
Jim Bedrick, FAIA // AEC Process Engineering
Jan Reinhardt // Adept Project Delivery
AGC/AIA BIMForum LOD Specification
www.bimforum.org/lod
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Specifying Deliverables
The Model Development Spec (MDS)
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Problems
•
How can the Owner get the
BIM(s) it wants?
•
How can the Owner evaluate BIM
deliverables?
•
How does the model author know
it is meeting its deliverables?
•
How much information needs to
be in a model?
•
How much effort will it take (how
do I price it?)
•
Who’s going to rely on it for what?
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We Never Had this Problem with
Paper Drawings – Why Now?
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Paper vs. BIM
Precision
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Paper vs. BIM
 Visual cues about state of development
 BIMs often carry unintended information
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Response?
The Disclaimer:
This model looks great so you can look at it but you can’t use it for
anything or rely on it for anything which includes, but is not limited to,
everything.
If you use it for anything anyway then you have to pay my lawyers
anything they want if I get sued for anything related to your use of the
model for anything.
Have a nice day.
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Response?
Disclaimer Approach:
Some of it’s not reliable so don’t rely on any of it.
Specified-Use Approach:
Some of it’s not reliable so only rely on
 what I say you can,
 for the purposes I say you can,
 to the degree of precision I say you can.
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Model Progression Spec
Level of Detail
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Model Development Spec
Level of Development
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LOD Definitions
→ LOD 100
→LOD 200
Conceptual
Generic
Placeholders
→LOD 300
→LOD 400
Specific
Assemblies
Details
Steel Braced Frame
$20-26 /sf
A/E/C Process Engineering
Copyright © AEC Process Engineering 2014
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Level of Development vs. Level of Detail
Level of Detail
• Looks like specific
steel shapes
• Location can be measured
precisely
Level of Development
• Have the shapes been
engineered?
• Are they in the final locations?
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LOD Definitions
 LOD 300
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LOD Definitions
 LOD 400
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LOD Definitions
 LOD 350
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AGC/AIA BIMForum LOD Specification
Bimforum.org/lodwww.bimforum.org/lod
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Clarifications
 LOD does not equate to a design phase
 There’s no such thing as an LOD ### model
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Adoption
Software Implementations
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Adoption
VA BIM Guide
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Parameters in models
The “I” in BIM
 Up until now LOD Spec only deals with geometry
 We want to capture and convey information using
models
 => Attributes associated with geometrical
elements
 What constitutes INFORMATION?
 Needs to be defined by the project
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Parameters in models
The “I” in BIM
 Objective:
 A) Define: What is required, and
 B) Define: What is NOT required
 Reliable definition enables:
 Methodical and automated checking of models
 Reliable models
 Computational methods
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Parameters in models
The “I” in BIM
 Challenge:
 Infinite number of attribute
 See Revit, IFC, Bentley, VA BIM guide etc.
 Populating the model with information requires
definition
 Which attributes are relevant?
 LOD Specification Part A: defines required geometry
 LOD Specification Part B: defines required attributes
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LOD Master Table
Attribute Breakout Tables
 Here is how it works
LOD Level
Uniformat
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Breakout table
A,B - Concrete
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Breakout table
A,B - Concrete
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Breakout table
D30 - HVAC
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Breakout table
D30 - HVAC
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Breakout table
D30 - HVAC
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Parameters in models
The “I” in BIM
 LOD Specification Part B:
 Use cases:




Quantity Take Off
Tracking of LEED items
Management of product information
Etc.
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Parameters in models
The “I” in BIM
 Limitations:
 LOD Spec Part B does not:
 Deal with attributes that can be derived from geometry
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Parameters in models
The “I” in BIM
 Next Steps
 Nov 15: release of LOD Part B for Review
 Dec 5: deadline for comments back to LOD
 Dec 31: Release of LOD Part B.
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