BIM and Interoperability for Precast Concrete Funded under a grant from the Charles Pankow Foundation
The Charles Pankow Foundation Advisory Committee November 28, 2007
Earle Kennett National Institute of Building Sciences
Charles Pankow Foundation Grant Project Team – – – – – – – – – – – – –
Earle Kennett, National Institute of Building Sciences Ric Jackson, FIATECH Charles Eastman and Yeon-Suk Jeong, Georgia Tech Rafael Sacks and Israel Kaner, TECHNION Davis Chauviere and Kelly Garcia, HKS Architects High Concrete Arkansas Precast Tekla Inc. Structureworks Inc. Autodesk Inc. Design Integrations (ArchiCAD) Bentley Inc. Gehry Technology
Integrated Work Process
Courtesy CH2M HILL
Design
Planning
BIM
Facility Lifecycle Concept Sustainment
Construction
Knowledge created over time
Functional Processes
Š Edgar 2006
Facility Lifecycle Helix
Facility Information Backbone
Knowledge created over time
Functional Processes
Š Edgar 2006
Facility Lifecycle Helix
Facility Information Backbone
Knowledge created over time
Functional Processes
Š Edgar 2006
Vendors
Facility Lifecycle Helix
Project Teams
Facility Information Backbone Functional Processes Knowledge created over time
BIM Interchanges
Š Edgar 2006
Vendors
Facility Lifecycle Helix
Project Teams
Business Process Value Chain
Contracted Exchange
Within NBIMS Scope
Not in Scope
Project Overall Goal The project sought to explore and define the functional requirements for a BIM standard for precast concrete. • Study two parallel design and detailing processes (2D CAD and 3D BIM) between precast concrete design and fabrication (3D Modeling Experiment) • Test building model data exchanges between BIM software and precast concrete fabrication software (Benchmark Date Exchange Tests) • Document efficiency comparison between 2D CAD and 3D BIM processes for precast concrete design and fabrication • Compile an Information Delivery Manual (IDM) for a precast concrete BIM standard
IFC File Tekla Model
Project Comparative Analysis
Current Practice 2D Architectural Faรงade - contract drawings Sketch layout of faรงades without drawing individual panels; connections not fixed
New Practice 3D Architectural Faรงade - contract model Assembly model with all piece marks identified; parts defined to reflect fabrication practices
2D Precast fabrication; Faรงades - & piece marks Re-drawn as assembly drawings; each piece then drawn from assembly, defining connections, embeds, passthrus, reinforcing
3D Precast Faรงade generate piece marks Refine assembly model; pieces modeled in relation to assembly model, with connections, embeds, pass-thrus, reinforcing
Shop Drawing coordination Production Floor Management Coordinate multiple drawing sets; management production on paper-based tracking
Shop Model coordination Production Floor Management All pieces in 3D make conflict checking simple, largely automated; materials, production tracked from assembly/erection model
2D BIM Workflow
3D BIM Workflow
19
Labor hours comparison Profession
Precaster
Activity
2D CAD
3D BIM
Productivity gain
Drafting
830
350
58%
Design
440
Total hours reported by Arkansas Precast: 830 + 440 = 1,270 hours According to PCI Journal benchmark (Sacks et al. 2005) medium-sized architectural projects consume 37.5 hr/1000sq.ft. This façade is 35,000 sq.ft. → 1,312 hours.
Sacks, R., Eastman, C. M., Lee, G., and Orndorff, D. (2005). "A Target Benchmark of the Impact of Threedimensional Parametric Modeling in Precast Construction." Journal of the Precast/Prestressed Concrete Institute, 50(4), 126-139.
Benchmark Data Exchange Tests
Architectural BIM Precast BIM
Structureworks
Tekla Structures
Revit
Bentley Arch.
ArchiCAD
Digital Project
Group A
Group B
ArchiCAD (V.10.0) IFC (SMC, TNO) Tekla Structures (R.13.0)
Bentley Architecture (V.8) DWG (AutoCAD) Digital Project (V1,R3)
Structureworks SAT or STP (Hoops)
Revit Building (V.9.1)
IFC DWG SAT or STP
Not supported Supported but not checked
Test Model
Part Structure
Part Structure
Representation of Building Elements in BIM Tools
ArchiCAD – IFC file - Geometric shape corrupted - More detailed explanation is needed
AC
IFC TS
BA DWG DP
SW SAT
RB
Bentley Architecture – IFC file - Façade panels are corrupted - More detailed explanation is needed
AC
IFC TS
BA DWG DP
SW SAT
RB
Digital Project – IFC file - No thickness of slab element
AC
IFC TS
BA DWG DP
SW SAT
RB
Revit Building – IFC file - No geometric shape errors
- Import the exported IFC file back • Geometry good • Some objects are changed into generic models (proxy elements)
AC
IFC TS
BA DWG DP
SW SAT
RB
Comparing Data Objects Used – Geometry Used ArchiCAD • IfcBuildingElement • IfcFacetedBrep – IfcClosedShell – IfcFace Bentley Architecture • IfcCurtainWall • IfcFacetedBrep – IfcClosedShell – IfcFace Digital Project • IfcBuildingElementProxy • IfcShellBasedSurfaceModel – IfcOpenShell – IfcFace Revit Building • IfcWall • IfcFacetedBrep – IfcClosedShell – IfcFace
Group A
Group B
ArchiCAD (V.10.0) IFC (SMC, TNO) Tekla Structures (R.13.0)
Bentley Architecture (V.8) DWG (AutoCAD) Digital Project (V1,R3)
Structureworks SAT or STP (Hoops)
Revit Building (V.9.1)
IFC DWG
ArchiCAD – IFC file - Tekla - Objects are modeled in boundary representation and not using higher-level geometry representation such as swept objects.
- The file does not contain any profile of objects. No conversion is possible where standard items do not appear in any IFC entity or attribute.
AC
IFC TS
BA DWG DP
SW SAT
RB
Bentley Arch. – IFC file - Tekla - Test file from Bentley Architecture export swept solids for walls, beams, columns and other objects. - However, no standard ‘profile’ name is retrievable. - Others are represented in B-Rep solids.
AC
IFC TS
BA DWG DP
SW SAT
RB
Digital Project – IFC file - Tekla - The file is invalid not as being IFC 2x3 certified but violates several side agreements that are addressed in IFC Building Smart ISG agreements, especially by exporting the Bezier curve. - Front panel objects, which are Windows, doors, staircases, are missing from the import because the objects are represented by surface model.
AC
IFC TS
BA DWG DP
SW SAT
RB
Revit Building – IFC file - Tekla - IFC file from Revit shows fewer problems. This does not mean Revit has best IFC interface, but more likely a best match with Tekla’s importing capability.
AC
IFC TS
BA DWG DP
SW SAT
RB
Details Revit Building ifc Model scale
O
Bentley Architecture
dwg
O
ifc
Diff
Digital Project
dwg
O
Default location and offsetting
Y (global) direction offset
ifc
ArchiCAD
dwg
ifc
dwg
X
X
O
X
X
X (global) direction offset
O
Left corner (perpendicular) Right corner (rounding) Top panels Middle relief
Top
geometry
O
O
O
O
X (missing)
X
O
O
Middle
geometry
O
O
O
O
X (missing)
X
O
O
Bottom
geometry
O
O
O
O
X (missing)
X
O
O
decoratio n
geometry
O
O
O
O
X (missing)
X
O
O
Upper gap
geometry
O
O
O
O
X (missing)
X
X
O
Top
geometry
O
O
O
O
X (missing)
X
O
O
Middle
geometry
O
O
O
O
X (missing)
X
O
O
Bottom
geometry
O
O
O
O
X (missing)
X
O
O
number
geometry
O
O
O
O
X (missing)
X
O
O
geometry
geometry
O
O
O
O
X (missing)
X
X: Not concaved
O
O
Not curved, upper right missing
O
X (missing)
X
X: No curve relief
O
Decorated window
geometry
O
Information Delivery Manual (IDM) data exchange requirements and workflow scenarios
•
Workgroup Formation & Definition of Requirements – Scope, stakeholders, industry need/potential adoption – Use case, process description – Universal & regional/local requirements
Workgroup Formation Process Map Exchange Requirements and Business Rules Standard Requirements
• Exchange Requirement Models
Exchange Design – Common concepts – Non-schema-specific data components
Generic Model View Definition Standard Design
Model View Definition and Implementation Specifications
•
Facilitate SW Product Implementation and Certification
Data Model View & Implementation Specification – For implementation in software – Facilitation and Certification of software implementation
Implementation in Software
Generic BIM Guide Product-Specific BIM Guides BIM Creation BIM Exchange and Data Validation BIM Data Reuse and Extension Use in Industry
NBIM Standard Development and Use
•
Software Used To Create BIMs in Projects – Guides describe exchanges regardless of software. – Guides by software vendors describe how their application supports the exchange requirements. – Project contracts can specify Standard exchanges. – BIM exchange files can be tested for correct content. – BIM data can be reused and repurposed.
PROGRAM
DESIGN
Barriers to Effective IFC Exchange • Non-uniform use of the BIM software • Non-uniform mappings between internal native objects and IFC schema objects • Variations in representations of geometry • Doman-specific objects missing from the IFC 2x3 schema
Domain-specific BIM Exchange Schema • Incorporate all of the basic building element objects that are needed in their native model schemas • Ensure that their IFC import and export translators incorporate all of the necessary objects and their relationships between the objects
CONSTRUCT
Generic BIM Guide Product-Specific BIM Guides BIM Creation BIM Exchange and Data Validation BIM Data Reuse and Extension Use in Industry
NEXT STEPS • Industry review of Information Delivery Manual (IDM) and Model View Definition (MVD) • Industry consensus • Software vendor implementation of final Model View Definition • Benchmark testing of software data exchange (test bed)