BIM IFC4 QTO, a practitioner’s perspective

SEAH Kwee Yong FSISV MRICS, buildingSMART Singapore JACIC’s seminar 5 Jul 2016

At the Grand Arc Hanzomon, Tokyo

updated on 29 May 2016

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Last Visited Tokyo in 2003 (SARS)

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Quantity Take Off (QTO)

Basic QTO (from IFC)

Calibrated Quantities/ Customised Quantities

Schedule of Rates (SOR)

SEAH Kwee Yong,

Chartered Surveyor/ Cost Engineer

FSISV, ICECa, MRICS,

MSc Property & Maintenance Management (NUS),

BSc Building (NUS ),

• Building and Construction Industry IT Standards Technical

Committee (BCITC) Singapore

• Measure Work Group, buildingSMART Singapore (bSS)/

Singapore Institute of Surveyors and Valuers (SISV)

• International BIM Work Group, Royal Institution of Chartered

Surveyors (RICS)

• BIM Manager/ Project Manager, Cyril K H Seah Architects

• Langdon & Seah (Retired 2013)

• Land Transport Authority Singapore (Retired 2008)

• Singapore Standard CP97 – Code of Practice for

Construction Electronic Measurement Standard (CEMS): o SMM for Building Works (part 1) and

o SMM for Mechanical and Electrical Works (part 2).

• Singapore Standard SS 527 – Code of Practice for Building

Project Document Control System

• bSS Technical Guide on BIM Object Library and

Collaboration

• Academic & Research Award for: “Excellence in

International Quantity Surveying and Cost Engineering”, by

the Pacific Association of Quantity Surveyors (PAQS) 2007

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History of IFC (open copyright) • Begin as Industry Alliance for Interoperability

• 1997 International Alliance for Interoperability (IAI)

• 1997 IAI Singapore Chapter started

• 2003 IFC2x2 launched (current standard IFC2x3)

• 2006 Revit “IFC Export” certified

• Challenging AEC on o “Open BIM”,

o with “BIM Execution Plan (BEP)”,

o for “Integrated Project Delivery (IPD)” through vendors’ Navigator

• 2009 IAI rebranded as buildingSMART International (bSI)

• 2013 IFC4 … yet to have vendors certified;

• Normative Reference: ISO 10303, Industrial automation systems and integration

• ???? ...For full implementation

• Implementation Phases suggested in country deadline

• Progressively working towards is termed “BIM Maturity index”

• AIA E202 Document “BIM Element Table” to monitor project progress

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Typical Expectation on BIM Manager

IFC Export • E.g. Revit can export Data on IFC format. An IFC certified

vendor would be able to support IFC (based on IFC2x2 to IFC2x3 currently).

• This export is not 100%, but for the basic essentials only.

• Properties of “Basic QTO” is one of them.

• Data beyond the basic, for example used by backend “Analyser” software to supplement Revit is not.

• Thus, it comprises the “Foundation Layer” only. Namely the basic 3D.

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Basic QTO vs Add on calibrated Quantities • IFC has a component on QTO, defining the parameters to be

“snapped” on.

• During IFC2x2, it had not been fully developed nor in consensus.

• IFC4 (known as IFC2x4 then) had re-designed the “Relational Database”, with QTO vendors and users.

• Basic QTO items would be expanded when vendors are certified for IFC4 compliance.

• IDM for whole new set of basic QTO is in progress; but only for the common ones.

• So localised items are not and has to be customised.

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capable of

QTO

Ad hoc or add on calibrated measurement

• Add formula as extension to basic QTO. Converting the basic

quantity with one or more dimension. – e.g. Weight converter

• Some formula suggested in IDM are too complicated.

• Some are for “staging” or “range” or “intervals” constraints,

such as “ceiling/ soffit height"; "excavation interval".

• A way to overcome is to simplify the “measuring rule” of the

Standard Method of Measurement (SMM).

• In Singapore, this simplification is done by SS CP97 CEMS -

SMM.

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• Can QTO stage-

transformation linked?

• Can past quantities be

reused?: o From i. Space;

o To ii. Element?;

o To iii. Composite as item?;

o To iv. BQ SMM items?

• Basic QTO for each stage? +

customised Take Off?

• “Take off process” has to be

“repeated” for each stage?

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IFC4

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Height, FinishCeilingHeight, FinishFloorHeight, GrossPerimeter, NetPerimeter, GrossFloorArea, NetFloorArea, GrossWallArea, NetWallArea, GrossCeilingArea, NetCeilingArea, GrossVolume, NetVolume

GrossPerimeter, GrossArea

GrossHeight, NetHeight, GrossPerimeter, GrossFloorArea, NetFloorArea, GrossVolume, NetVolume

Height; EavesHeight, FootprintArea, GrossFloorArea, NetFloorArea, GrossVolume, NetVolume

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Export a Project to IFC Save a project as an IFC file for use with an IFC-certified application that does not use the RVT file format.

From Revit Guide

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Estimate With

just Basic QTO

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Revit Export .dwf for 5D BIM CostX Estimate

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CostX picking Revit’s .dwf by “Object”

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Naviswork quantitiesChoose

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Other practice initiatives • RICS New rules of measurement for building works

(NRM) o NRM 1 - Order of cost estimating and cost planning for building

works. Elements, systems, sub systems and components.

o NRM 2 – Detailed rules for measurement and description of building works. Trade based classification system

o NRM 3 – Order of cost estimating and cost planning for building maintenance works. Extension of NRM1.

o http://www.designingbuildings.co.uk/wiki/NRM2

o http://www.isurv.com/site/scripts/download.aspx?type=downloads&fileID=6531

• COBie (BS 1192-4:2014) Collaborative production of information Part 4: Fulfilling employer’s information exchange

• 4D, 5D integration – From “objects” Properties (IFC QTO) Formula calibrated-Quantities

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Hurdles • Need to synchronise meaning of terms e.g. GFA

o Gross Floor Area (usage x) is not the same as GFA (usage Y) and is affecting input

to Assets Information Model

o RICS introduces International Property Measurement Standards (IPMS) to address

and understand the country differences in the definition of GFA (usages)

• Need to synchronise “Digital Building Block” o A structured common Library of BIM Object for commonly used items “in a shared

context” – e.g. Country Based; and therefore a possible Object related Cost

Library

o An associated customised QTO (i.e. formula extension) can be developed for

“reused” or lookup as reference. (e.g. plug in in HELIOS)

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BIM Maturity; Index?

How much can practitioner influence?

CAD Vendor + Intermediate 5D Vendor + Practitioner

Object library detail + Cost library detail link

e.g. http://www.vicosoftware.com/products/Vico-Office/tabid/85286/Default.aspx

Architectural Objects,

Structural Objects,

MEP Services Objects

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Thank You

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http://au.autodesk.com/au-online/classes-on-demand/class-catalog/2014/revit-for-architects/sd6060#chapter=1

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