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buildingSMART alliance COBieLite: A lightweight XML format for COBie data

COBieLite: A lightweight XML format for COBie data

by Chris Bogen, PhD and Bill East, PhD, PE, F.ASCE
Engineer Research and Development Center, U.S. Army, Corps of Engineers

Introduction

The National Building Information Model (BIM) Standard - United States™ is a standard comprised of several different types of content. One of these content types is an "information exchange" standard. Information exchange standards are non-proprietary specifications for the delivery of building information. Such specifications have the potential to integrate information found in typical contract deliverables used.

One of the most widely used NBIMS-US information exchange standards is the Construction-Operations Building information exchange (COBie). The purpose of COBie is to identify and exchange information regarding managed facility assets, starting at the planning of a project, and continuing through the entire project life-cycle. During this life-cycle, the most obvious application of COBie is as a replacement to the current paper-based construction handover documents.

Many of the parties that create information that feeds COBie perform their work using business processes and software that does not require the full weight of building information found in a complete construction handover dataset. As a result a sub-specification of COBie is required to enable such software to deliver just that needed portion of information without the overhead of the entire COBie or BIM framework. The Life-Cycle information exchange (LCie) project demonstrates where, through the entire life-cycle of a generic project, COBie information is created. Central to understanding COBie, and as defined in LCie, is understanding that most exchanges of COBie information do not require the entire set of COBie data found at the construction handover.

COBie files are formatted to support two distinct types of work flows. The first work flow is the exchange of COBie information by software systems that could produce and consume COBie data in its underlying standard format, the Industry Foundation Class Model. The second work flow is one which would have the widest possible visibility to practitioners in the planning, design, construction, and operations fields. This second format, a spreadsheet format, has also been widely adopted in software focusing on the needs of builders and operators.

Requirement

A new workflow for COBie data has emerged since publication of the two original COBie formats, STEP Physical File Format (i.e. IFC) and COBie Spreadsheet, in 2007. Since 2007 there has been a revolution in information technology related to hand-held and remote sensing devices. These innovative devices do not need access to an entire set of COBie data, but need only to interact with one of the small parts of the data set for purposes that may have nothing directly to do with the delivery of the construction handover data set. Furthermore, spreadsheet XML COBie files contain non-relevant information such as text style, row height, column width that is only meaningful to spreadsheet applications. As a result, there is a need for a more generic specification for the exchange of COBie information between software applications.

Description

COBieLite is designed as a National Information Exchange Model (NIEM) compliant XML specification for COBie that simplifies the delivery and use of facility asset information for application programmers outside the typical architects, engineers, builders, and managers who already use COBie in IFC or SpreadsheetML formats. In short, the COBieLite XML Schema is for programmers what the COBie spreadsheet format is for architects, engineers, builders, and managers.

The "Lite" term is included in the name of this new COBie XML deliverable format because its underlying schema is:

  1. Explicitly represented in an XML Schema declaration. Thus, programmers do not have to filter through the various COBie project pages and COBie spreadsheet examples to begin programming applications that exchange COBie data.
  2. Free of unnecessary data about spreadsheet workbooks, worksheets, text style, etc.
  3. A less computationally expensive way to reconcile COBie decomposition relationships (e.g. Facility → Floor → Space). The COBieLite schema uses parent-child nesting to represent decomposition as much as possible while minimizing the use of computationally expensive table key references that appear throughout the COBie spreadsheet format.
  4. Designed to be re-used in Life Cycle information exchange (LCie) lightweight subschema that represent COBie enterprise application Create, Read, Update, and Delete (CRUD) transactions.

At its core, COBieLite is a NIEM-conformant XML document schema, and it is supported by an integrated development, documentation, and testing tool freely available through Creative Commons License from the OASIS Content Assembly Mechanism (CAM) project. Additionally, COBieLite is supported by numerous other applications and programming libraries that process XML schemas, e.g., Microsoft Visual Studio, Altova XML, SAXON XML Parser, and Apache XML Beans for Java.

Application

COBieLite is mapped to and from both the Facility Management Handover Model View Definition specification of the Industry Foundation Class Model (for IFC 2x3 and 2x4) and the COBie SpreadsheetML format (2.4) as a result COBie is simply another format in which the NBIMS-US standard COBie data maybe delivered.

COBieLite import, export, and checking tools will also be provided as an option in the open source bimServer.org to demonstrate the use of lightweight XML packets in the context of the LCie project. A COBieLite Export is already available in the free COBie Toolkit.

Software vendors may also wish to use the tools freely provided through the OASIS Content Assembly Mechanism (CAM) project to validate import and export of COBieLite files.

Current Status

The artifacts presented in this page are designated as Release Candidate Four, and future releases will be provided through updates to this page. The Version will be promoted from "Release Candidate" after the publication of the US National Building Information Modeling Standard (NBIMS) v03 where COBieLite appears in the COBie 2.4 ballot.

Download Options

You may download a .zip of all COBieLite RC2 resources (COBieLiteRC2 All Resources)or download individual components listed below:

Schema Resources

The following COBieLite materials, provided in advance of the official release, are for evaluation and planning purposes only.

CAM Toolkit

COBieLite RC4 CAM Template

COBieLite RC4 CAM NIEM Evaluation

COBieLiteRC4 Tabular Documentation

COBieLiteRC4 XML Schema

COBieLiteRC4 MindMap using FreeMind

COBieLite RC4 XML Document Examples With Errors (ZIP) – These error examples were generated by CAM and are provided to provide examples for testing and validation.

LCie Example

Business rules for COBieLite are implemented at the specific LCie exchange specification level. The dictionary for COBie and all Product Type related LCie business rules is included in the XML Schema Resources file listed below. Since there are could potentially be hundreds of example create, read, update and delete transactions, a limited set of examples on one LCie data exchange (Product Installation Report) are provided.

LCie Example: Product Installation CAM Template

LCie Example: Product Installation Tabular Documentation

LCieExample: XML Schema Resources (ZIP)

LCie Example: Product Installation MindMap using FreeMind

LCie Example: Product Installation Report XML Document Examples (With Errors) (ZIP) – These error examples were generated by CAM and are provided to provide examples for testing and validation.

Common BIM File Examples

COBieLite Clinic Handover Example

LCie Example: Clinic Product Installation

References

COBie

LCie

Common BIM Models

OASIS Content Assembly Mechanism

Change Log

Release Candidate 4:

  • Revised introductory text to more adequately describe COBieLite
  • Compacted the extraneous namespaces introduced in Release Candidate 3. Though the RC3 design was elegant (from an Object-Oriented programming point of view), it was too complex for some XSD tools to validate and generate optimal code.
  • Added LCie core schema, product data exchange subschemas, and example files
  • Changed namespaces
  • Corrected various bugs
  • Updated COBieLite Example file

Release Candidate 3:

  • Created namespaces for each COBie element so that each could be used in substitution group replacement of abstract elements defined in the core COBieLite schema. This revision was made while designing the LCie sub-schema and was intended to provide an elegant solution to the re-use of common substitutions.

Release Candidate 2:

  • COBieLite schema changed so that only the essential XML elements and attributes are required (primary and foreign key elements).
  • COBieLite schema changed so that, when possible, the order of XML elements is not restricted (i.e. use of xs:all when possible instead of xs:sequence)
  • Added missing units of measure to area, length, and volume enumerated types
  • Corrected the Zone key to ZoneName, ZoneCategory instead of ZoneName, SystemCategory
  • Corrected issue in .cam files where a number mask rule was unintentionally inserted for all decimal values
  • Changed example files to be compatible with RC2

Release Candidate 1:

  • Everything is new

Licensing

All specifications, documentation, examples, and ancillary materials provided here by buildingSMART alliance are licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License.

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