Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Victor GanePhD Candidate, CEE [email protected] 214October 19, 2009Product modelsRepresentations of designs, design spaces, and their application at early design stages12Big Ideas Design(v) represents:- Problem definition / solving- Creating Design Spaces (n)- Artifacts as designs (n) Design stages:- Conceptual design- Design development- Design implementation  Conceptual stage- Augmented by (my) innovative computer-implemented design methodology called Design ScenariosAgendaOverview - Design process- CAD- BIM- Parametric modelsDesign Scenarios process- Objectives- Methods- Simple exampleLab Wednesday, Oct 21Design processProblem definition (Ditier, 1983)- Identify basic requirements- Define resulting problem- State parameters defining the design space Design space∑ problem space, solution space, design process Krishnamurti (2004)Problem space Design requirementsSolution space all candidate solutions for a given design problemDesign processmethods to develop candidate solutions from requirementsProblem solving (Ditier, 1983)- create design alternatives- evaluate each alternative- isolate preferred solutions- implement that solution3CAD – why & when?What is CAD?- Computer 2D/3D graphic representation of intended design - Use of geometric modeling, interactive graphics, reuse stored information- Predictable and repeatableWhen did it start?- SAGE (Semi-Automatic Ground Environment – US Air Force) – mid 1950s- Hanratty (early 1960s – GM Research Lab) – early contributions to CAD- Sutherland (1963 – MIT PhD dissertation) – Sketch PadPatrick Hanratty Sketch PadSAGE4CAD – milestonesBy 1970 50 companies world wide were using CAD; <1% of manufactured parts designed with CADMid 1970s first 3D CAD applications, wireframe modeling (ambiguous & limited ability to represent curved surfaces)1982 Dassault’s CATIA V1 (3D design, surface modeling, NC programming);Autodesk AutoCAD 86 for IBM PC1983 Autodesk AutoCAD V1.2, 1.3, 1.41984 Gabor Bajor writes in Pascal 3D CAD program (Graphisoft);AutoCAD V2 (isometric, attributes, DXFIN & OUT, snap, etc)1985 CATIA V2 (integrated drafting, solid & robotics functions) – becomes aeronautical applications leader;AutoCAD V2.1 (3D capabilities, polylines)1986 AutoCAD V2.18 (AutoLISP)1988 CATIA V3 (becomes automotive applications leader)1989 Parametric Pro ‘s T-FLEX (1st parametric mechanical CAD)Parametric Technology’s ProEngineer V1 5 CAD mass adoption was made real with the introduction of microprocessorsTraditional CAD – basic conceptsCoordinate systems:  model & display 2D / 3D data6Cartesian Coordinate SystemSpherical Coordinate SystemCylindrical Coordinate SystemTraditional CAD – basic conceptsModeling:  primitive geometric elements (points, lines, arcs, splines etc) 2D vs 3D  Wireframe / Surface / Solid7Wireframe models(ambiguous)Surface models Solid models solid modeling significantly improved design representationTraditional CAD – basic conceptsVisualization isometric / perspective / planar views (1st vs 3rd angle projection) wireframe, hidden, rendered – zoom, pan, redraw81st angle projection 3rd angle projectionwireframehiddenrenderedTraditional CAD – basic conceptsEditing erase trim  scale  rotate  move stretch, etc.Managing  layersCalculating  area volume centroid dimensioning labeling, etc.9Traditional CAD – limitations drafting tools  support project visualization & documentation static models  time consuming editing process no attributes  limited model use in analysis / simulation tools10Similar to manual draftingBuilding Information Modeling (BIM) - definitionBIM is: creation & use of coordinated & consistent information about a building project used for: Design decisions (renderings of 3D models) Producing standard compliant construction documents  4D scheduling & sequencing Calculating quantities / cost-estimating (5D) Managing design change Managing and operating the facility11Building Information Modeling (BIM) - conceptsBased on the concept of Product Data Management (PDM) Creating a single database with all design related information Integrating with model based analysis tools Creating a common platform accessible to all participants Improving communication between stakeholders  Promoting reuse of existing data12Building Information Modeling (BIM) - conceptsMain distinctions:  Operates with 3D models only  Object-oriented CAD (capture/manage information about a building) Quantifiable & Query-able  Assemblies of parts Records of interaction with the model (who changed what & when) Integrated, multidisciplinary design approach13Building Information Modeling (BIM) - Vendors BIM vendors have different approaches of interpreting BIM but are focused towards a common goal of creating a single central data base14Building Information Modeling (BIM) - limitations Not all BIM tools suited for conceptual design- Hard to iterate in a short time- Hard to achieve different levels of content abstraction (i.e. quickly makes the CAD model “heavy”)  BIM is strong once design is determined and needs to be rationalized Some BIM tools may still lack comprehensive geometric constraining capabilities 15Parametric modeling - definition Constraint–based, associative modeling- procedural, algorithmic description of geometry- parameters of a particular design are declared, not its shape- associations offer opportunities to formalize design- relationships can be revised during the design process16Parametric modeling - concepts global(affect multiple elements)output (no user control; value changes as a result)input (user can actively control value)local(affects single element)17Parameters – used to define geometryParametric modeling - conceptsnumeric (define geometric elements)geometric (relationships between geometric elements)underconstrained (missing constraints)overconstrained (conflicting constraints)18Constraints - relations that limit the behavior of geometryParametric