Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 3-D Parametric Modeling of Buildings

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 2 Introduction Rework in construction The distinction between drafting and modeling What are parametric relations in models? Software Implementations Applications in Construction Automation of Design and Detailing

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 3 Rework in construction “Rework is the unnecessary effort of re-doing a process or activity that was incorrectly implemented the first time…. The direct costs of rework in construction projects are considerable and have been found to be …” (Love et al. 2000, Construction Management and Economics) 10-15% of contract value

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 4 Sources of Errors and Rework (Josephson and Hammarlund 1999, Automation in Construction)

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 5 The distinction between drafting and modeling

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 6 Drawing CAD provides an ‘electronic drawing board’ Drawings contain the information Human readable – data input required for analyses Coordination is difficult Manual checking No support for production

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 7 Modeling CAD enables a parametric model Model contains the information – drawings are only reports Computer readable – direct analyses possible Coordination is automatic Automated checking Full support for production

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 8 Drawing vs. Modeling CAD provides an ‘electronic drawing board’ CAD enables a parametric model Drawings contain the information Model contains the information – drawings are only reports Human readable – data input required for analyses Computer readable – direct analyses possible Coordination is difficultCoordination is automatic Manual checkingAutomated checking No support for productionFull support for production

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 9 Some adjective definitions… “information-rich, parametric 3-D, and integrated computer-modeling of buildings.” “information-rich, parametric 3-D, and integrated computer-modeling of buildings.” “information-rich, parametric 3-D, and integrated computer-modeling of buildings.” “information-rich, parametric 3-D, and integrated computer-modeling of buildings.”

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 10 “information-rich” Function information Behavior information State Enable operation of design, analysis and other software directly

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 11 “parametric 3-D” For example: Solidworks, Tekla Xsteel, etc.

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 12 3-D Parametric Model Example

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 13 Another example….

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 14 “integrated” Process planning application Design application Analysis application Shop drawing Application Integrated Precast/ Prestressed Data model Rebar bending application Design Stage Architect or contractor Formwork design application Production Stage Robotics applications Logistics and production app. Scheduling and workflow app. Materials order/ tracking app. Enterprise Applications Material suppliers “B2B” exchanges Formwork fabricator Outside Exchanges Internal Exchanges (Eastman & Augenbroe, 2000, presentation to PCI ) Links to management information (schedule, costs, QC, etc.)

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 15 Parametrics at Assembly Level

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 16 Parametric - Concepts Floor 6 Floor 5 h2 d2 h1 d1 d3 d1 = d2 + d3 + h2 Driving Parameter Derived (or driven) Parameter

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 17 Parametrics and Design Intent Floor 6 Floor 5 > Minimum railing height h2 > Minimum ledge depth d2 > Minimum head room h1 d1 > Minimum beam design depth d1 d3 d1 = d2 + d3 + h2 ? d1 = (L6 + h2) – (L5 + h1) ? L5 L6 > Minimum beam depth

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 18 Software Implementations General Parametric Modelers (mostly mechanical) CATIA, Solidworks, Inventor, etc. For AEC (architecture, engineering, construction) Revit (Autodesk)RevitAutodesk ArchiCAD (Graphisoft)ArchiCAD Architectural Desk Top in AutoCAD (Autodesk)Autodesk Microstation Triforma (Bentley)Bentley

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 19 Applications in Construction Conceptual design; Automated building design Automated detailing (object methods with parameters enable assemblies and parts to ‘design themselves’) (e.g. IPTs)IPTs Automatic production of shop drawings or CNC control data Component libraries – ‘intelligent objects’ (e.g. objects’

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 20 Automation of Design and Detailing Top-down assembly design

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 21 Potential for Eliminating Errors I.The logical relationships between connections and pieces are embedded within the system. II.The 3-D model is the single source for all the product information. III.Automated detailing. IV.Building systems that impact on the sturcture or other elements can be modeled. V.Automated design checking routines.

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 22 Of the 22 errors discussed for Precast, all are considered eliminated with at least medium confidence 16 (73%) with at least high confidence 11 (50%) with complete confidence Potential for Eliminating Errors

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 23 Conclusions Modeling a building in a computer, instead of drafting multiple representations of it and of its parts in drawings (whether CAD or manual), holds the potential to reduce the occurrence of errors and the need for rework in construction projects.

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 24 Conclusions Employing 3-D CAD is necessary, but not enough. The building model must be: an integrated parametric model, comprehensive – include all details, cover as much of the project scope as possible, drive the production of all drawings and reports.

Strategies for IT Adoption in the Building Industry © 2002 Prof. C.M. Eastman & Dr. R. Sacks 25 Conclusions Other benefits of 3D and automation: reduce lead-time from months to days, integrate with management systems, integrate with production systems, increase responsiveness to change, reduce engineering costs.