1. Structuring BIMs for
IFC and COBie
Robert A. Feldman, PhD
Gregory R. Williams, AIA, LEED AP
Kristine Fallon Associates, Inc.
February 23, 2012
2. Acknowledgements
The research presented here was funded by:
US Army Corps of Engineers
Engineer Research and Development Center
Construction Engineering Research Laboratory
Champaign, Illinois
3. Objectives
1. Define COBie and explain how it is used on projects.
2. Discuss the importance of information standardization.
3. Review process for extracting COBie data from a
Building Information Model.
4. Identify limitations of current software packages used in
this workflow.
5. Discuss how and why COBie and IFC are being utilized
by the GSA.
4. What is COBie?
• Construction Operations Building Information Exchange
• COBie is based on the IFC Model View Definition for
Facilities Management Handover
• COBie's focus is on delivering building information for
facilities management, not geometric modeling
• In simplified terms, COBie is IFC in the form of an Excel
spreadsheet
7. Objectives of ERDC Project
• Develop, document, and create three consistent
baseline building information models with specific
architectural, structural, plumbing, electrical, heating
and ventilating information
• Document the methodology used to create these
models and the IFC/COBie output to assist others in
meeting contractual requirements
8. The ERDC Report
http://buildingsmartalliance.org/
index.php/projects/commonbimfiles/
9. Successful Information Transfer
Requires Standards
“Key to the ability to exchange intelligent building information across system
boundaries is agreement on the types, hierarchy and content of the data objects
that make up the building model.”
Source: General Buildings Information Handover Guide: Principles, Methodology, Case Studies (NISTIR 7417)
10. Successful Information Transfer
Requires Standards
• Not just formats!
• Common schema
• Content to be transferred
• Properties (attributes) to be included
–Which properties are needed
–Naming standards for those properties
11. Methodology
• Use IFC Data Model as the schema
• Develop Common Object Library
• Create Models
• Export to IFC
• Convert IFC to COBie Spreadsheet
12. Model Development
• Create and use a Common Object Library
• Develop models to the “Coordinated Design”
or “60% Design” phase
–Show details typical of ¼” = 1’ scaled drawings
–Include the following disciplines:
• Architectural
• Structural
• Mechanical
• Plumbing
• Fire Protection
• Electrical
13. Project Tools
• Software
– Autodesk Revit Architecture 2011
– Autodesk Revit MEP 2011
– BIMServices (AEC3 UK Ltd) v2010-12-28
with _asCOBIE2.xml.xsl dated 2011-04-06
• Building Components (Common Object Library)
– Use standard Revit content as much as possible
– Add additional parameters as shared project parameters
14. Common Object Library
• Define consistent objects for use in multiple
models
• Include common properties needed to
produce IFC and COBie deliverables
–Add properties (Shared Parameters in Revit)
–Standardize property naming based on IFC and
COBie terminology
15. Common Object Library
• 56 Revit System Families
• 103 Component Families
–87 Standard Revit Library
–11 Autodesk Seek
–3 Custom
• Revit shared parameter file
http://buildingsmartalliance.org/
index.php/projects/commonbimfiles/
16. The Models
• 3 Building Models:
–Duplex Apartment
–Office
–Clinic
http://buildingsmartalliance.org/
index.php/projects/commonbimfiles/
17. Getting from Model to COBie
• Each vendor creates one IFC translator that
can serve multiple downstream programs
GSA
Validation
Revit COBie
IFC
Maximo MIMS
Energy
Analysis
18. Getting from Model to COBie
• Each vendor must create a separate Revit
translator for each transfer
GSA
Validation
IFC COBie
Revit
Maximo MIMS
Energy
Analysis
19. Revit-IFC-COBie Data Transfer
• Revit IFC export and BIMServices will populate
these COBie tabs (8 of the 10 GSA-required tabs):
–Facility
–Floor
–Space
–Type
–Component
–Attribute
–(Zone and System information export as attribute data)
20. Revit-COBie Data Transfer
• Revit COBie2 Add-in can populate 5 COBie tabs
• Requires manually copying information from Revit
schedules to COBie spreadsheets
• COBie properties in Revit are not given standard
COBie names
21. Limitations of the Revit-IFC Approach
• Revit export categories are broader than IFC types
• Many Revit objects did not export properly unless their
export category was changed or specified in special
parameters
– IfcExportAs and IfcExportType parameters had to be added to 31 of
the 103 component families
– Export category names for Cable Trays and Conduits had to be
changed to match IFC categories
– Revit Generic Models and Specialty Equipment categories were
changed to other categories in order to translate properly
• Non-standard component naming:
M_Single-Flush:1250mm x 2010mm:1250mm x 2010mm:146678
22. BIMServices Limitations
• Duplication of some data by BIMServices
–Values in 10 fields on 5 tabs duplicated
–Manually edited to correct the published files
• IFC files larger than 25MB cause “Out of
Memory” errors
–Model must be partitioned into smaller sections,
breaking up MEP systems, which results in the loss
of information
• The new COBie plug-in for the open-source
BIM Server (bimserver.org) works better
23. Why are Organizations Using COBie?
The General Services Administration (GSA) has incorporated
IFC and COBie requirements into their latest BIM guidelines.
• The GSA is the largest property owner in the US – 362 million rentable
SF
• A study by the National Institute of Standards and Technology (NIST )
discovered that large sums of money was being wasted looking for,
validating, and recreating facility information that should have been
readily available.
• COBie provides an open standard format for capturing project data
when its generated and minimizes information exchange loss and cost
typically associated with physical handover of paper documentation.
24. GSA’s BIM Guide for Facility Management
The GSA’s BIM Guide for Facility Management (FM)
provides the structure to address organizing and tracking
information through all phases of a facility’s lifecycle.
• Identifies the work processes and information requirements.
• Evaluates methods for capturing and recording information updates.
• Defines the scope of information that should be included or updated
in the record BIM
• Defines technology requirements for accessing and updating BIMs
25. Summary
• Properly structured BIMs are needed to achieve usable output
• COBie is based on the IFC Model View Definition for Facilities
Management Handover, so IFC output from BIM authoring tools
easily converts to COBie spreadsheets
• Since IFC deliverables will be required by GSA and the IFC file
can be used for multiple purposes, direct conversions from a
BIM application to COBie are not a good long-term strategy
• Current state of the technology has limitations
– Need consistently structured BIM content, including standardized
element property sets
– Need better IFC export
• COBie provides framework for standardizing information for the
lifecycle of a project
26. Q and A
Thank You!
• For more information on topics discussed during this
presentation, check out the following links:
•Experimental BIM Report: http://buildingsmartalliance.org/
index.php/projects/commonbimfiles/
•COBie : http://www.wbdg.org/resources/cobie.php
• IFC: http://buildingsmart-tech.org/specifications/ifc-
overview/?searchterm=ifc
•BIM Services: http://www.aec3.com/en/index.htm
•BIM Server: http://bimserver.org/
•BIM Server COBie Translator: http://buildingsmartalliance.org/
index.php/projects/commonbimfiles/
•GSA BIM Guide Series: http://www.gsa.gov/portal/category/21062
