Fundamental of 3D modeling

SPPU Solid Modeling and Drafting

1. Savitribai Phule Pune University
Second Year of Mechanical Engineering (2019Course)
Course Name : Solid Modeling & Drafting(202042)
Unit No. I : Fundamentals of 3DModeling
Preparedby,
Mr. Hemant BWagh
AssistantProfessor
Department of MechanicalEngineering
Matoshri College of Engineering and Research Centre, Eklahare,Nashik
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2. Syllabus
UnitIFundamentalsof3DModeling
Introduction,ProductLifeCycle,CADtoolsinthedesignprocessof
ProductCycle,ScopeofCAD,SoftwareModules-OperatingSystem
(OS)module,Geometricmodule,applicationmodule,programming
module,communicationmodule,ComputerAidedDesign-Features,
requirementsandapplications
3DModelingapproach-Primitive,FeaturesandSketching,Typesof
Geometricmodels-2½extrusions,axissymmetric,composite,3D
&solidmodeling,objects,differencebetweenwireframe,surface
Modelingstrategies
Model viewing: VRML web-basedviewing
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3. What aboutCAD
Computer-Aided Design (CAD) is use of computer systems to
assist in the creation, modification, analysis, and optimization ofa
design.
Modern CAD system are based on Interactive ComputerGraphics
(ICG) system in which computer is used to create, transform, and
display data in the form of pictures orsymbols
The ICG system and the human designer are themajor
components of a CADsystem.
Interactive computer graphics is a tool used by the designerto
solve a designproblem.
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4. Need ofCAD
To remain competitive in globaleconomy.
New products with enhanced features atcompetitive
costs.
Reduction in product lifecycle.
Reduction in manufacturing cost and deliverytime.
Increasing consumer awareness aboutquality.
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5. Different terminology relatedCAD
Computer-AidedManufacturing
(CAM)isthetechnologyconcerned
withtheuseofcomputersystemsto
plan,manage,inspectandcontrol
manufacturingoperationsdirectlyor
indirectly.
Computer-Aided Engineering
(CAE)isthetechnologyconcerned
withtheuseofcomputersystemsto
analyzeCADgeometry,allowingthe
designertosimulateandstudyhow
theproductwillbehave.
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6. Component of CADsystem
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7. HardwareComponents
Graphic device is composed of a processing unit, adisplay
device, and one or more inputdevices.
InputDevice
Mouse
Space ball
Data tablet with apuck
Keyboard
OutputDevice
Plotters
Color laserprinters
LaserDisplay
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8. SoftwareComponents
CADsoftwareallowsthedesignertocreateandmanipulatea
shape interactively and storeit
CAM software plans, manages and
controls the operations of amanufacturing
site
CAE software analyzes design geometry,
allowing designer to study productbehavior
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9. Product LifeCycle
Introduction:
“It is the process ofa product goes through from when it is
first introduced into the market until it declines or is
removed from themarket.”
The life cycle concept may apply to a brand or to a category
of a product.
It’s duration may be as short as a few months or years,
depending on theproduct.
As a product progresses through the stages, changes are
made to how the product ismarketed.
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10. Four Stage of Product LifeCycle
1.Introduction
2.Growth
3.Maturity
4.Decline
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11. 1.IntroductionStage
The product is initiallypromoted.
Public awareness is very important to the success of a
product.
To build demand for the product and get it into the hands of
consumers, hoping to later cash in on its growingpopularity.
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12. 2.Growth
Product starts togrow.
Very large amount of money is spent onadvertising.
The ways to prompt aproduct.
Success in advertising strategy increases thesales.
Marketing in this stage is aimed at
increasing the product's marketshare.
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13. 3.Maturity
Sales grow at a very fast rate and then gradually begin to
stabilize.
Also called "shake-outpoint."
Begin innovating to maintain or increase market share,
changing or developing the product to meet with new
developingtechnologies.
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14. 4.Decline
Consumer demandreduces.
Many companies decide to withdrawal their Products from
the market due to thedownturn.
The only way to increase sales during this period is to cut
production costs and reducespending.
Time to convey the customer to shift over the product (New
technology.)
E.g. Operatingsystem.
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15. Case Study : TATA NANODevelopment
The People'scar
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16. DesignNeed
“I saw families ridingaround
on scooter with kidsstanding
up and the mother carrying
baby and sitting pillion and
decide to something about it.
I stated as a quest for an
affordabletransports
solution”.
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17. Design Definitions,Specification
Affordable
Meet safetyrequirement
Fuelefficient
Concept/ alternative design testing andDevelopment
Scooter with 2 extrawheels
3 Wheelercar
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18. Design andanalysis
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19. Tata Motors has applied for patent protection for over 37 inventionsand
innovations
(Source : ET 16march2009)
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20. Tata Nano Sanand AssemblyPlant
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21. Product lifecycle
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22. Product lifecycle
Product life-cycle is the succession of strategies by business
management asaproductgoes through itslife-cycle.
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23. 1.Introduction
The Nano car hit the Indian market in the2008.
It drew quite a lot of attention from the mediaacrosstheglobe and
also Indians as it the “world’s cheapestcar”.
Thesalestargetwastosellaround250,000carsper annum in the
year2008.
2.Growth
Tata Nano saw an incredible amount of sales in the followingyear.
It was the second best sellingcarinthe2011.
Withthefactoryoutputincreasingfrom30,000to70,432to74,52in
theyear2008,2009and2011respectivelyNanowasonitswayto
success.
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24. 3.Maturity:
Nano had established itself in the Indian Automobile market as it
was bought mostoften.
Italsopushedthe sales of Maruti 800 the next cheapest car down
by20%.
This was seen was a greatestachievementas it had pushed down
its retest competitor Maruti800.
4.Decline:
The product is very well in themarket.
It also launched a higher version of it product Gen X in2014.
However, the Nano faced lot of free economic cars launchedby
other player like HyundaiEon,MarutiAlto which is also priced
around the same figure as TataNano.
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25. ProductCycle
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26. Product Cycle withCAD
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27. CAD tools in the design process of ProductCycle
DesignPhase Required CADtool
DesignConceptualization Geometric modellingtechniques,
graphics aids,visualization
Design modelling andsimulation Animation, assemblies, simulationand
special modellingpackage
Designanalysis Analysispackages
Designoptimization Customizedoptimization,
structuraloptimization
DesignEvaluation Dimensioning, tolerances,BOM
DesignCommunication Drafting and detailing, shadedimages
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28. Scope ofCAD
Twomainprocess:Design+Manufacturing
Twosub-processofdesign:Synthesis+Analysis
CADissubsetofdesignprocess
CAMissubsetofmanufacturingprocess
ActivitiesoftheCADprocessincludemassproperties,
FEA,dimensioning,tolerance,assemblymodeling,
generatingshadedimages,documentationanddrafting
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29. DigitalMockup
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30. FEA
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31. ProductDocumentation
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32. SoftwareModule
Theirarenumberofsoftwarepackagesareavailablefor
variousCADoperationsandeachhasitsownstrengthand
uniqueness.
EachCADsoftwarehasitsownstrengthanditusuallytargeted
towardasspecificmarketandgroup,accordantlythesoftware
modulesaredesign.
Therearedifferentmechanical,electrical,architectureCAD
software'sareavailableforrespectiveusers,buteachpackage
hascommonstructureandmodules.
Soawarenessofthisstructureandmodulesenabletheuserto
understandbettersystemfunctionsforbothevaluationand
trainingpurposes
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33. 1.Operating System Module (OS module)
CAD software is written in FORTRAN and Clanguages.
FORTRAN provides the number crunching, whereas, C
language provides the visualimages.
Networking is an important consideration in applicationsof
CADsoftware.
A model created by one engineer must be readily accessibleto
others in an organization, which is linked by a LAN or other
mean.
The designer, analyst, management, marketing, vendor,and
others generally share amodel.
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34. 2.GeometricModule
It is heart of CADsystem.
Provide various function to perform geometric
modeling, construction, editing, manipulationof
existing geometry, drafting anddocumentation.
Ultimate goal is able to utilize the model fordesign
and manufacturingpurpose.
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35. 3. Applicationmodules
Usedfordesignandmanufacturingpurpose.
Thismodulevariesfromonesoftwaretoanother.
Howevertherearecommonapplicationsshareby
mostpackages.
Mechanicalapplicationincludemassproperty
calculation,assemblyanalysis,toleranceanalysis,
FEA,simulationanalysisetc.Manufacturing
applicationincludeprocessplanning,NC,CIM
etc
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36. 4. ProgrammingModule
Itprovidesinformationrelatedtoprogramming
languagewhichisusedforanalysisandcalculation
purpose.
Allowsusertocustomizesystembyprogrammingthen
tofitcertaindesignandmanufacturingtask.
Requiredadvancedknowledgeofsystemandits
databaseformat.
Higher level format such as C,C++,JAVA,MATLAB
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37. 5. CommunicationModule
Itiscommonnetworkusedtotransferthedatabase
modelforanalysispurposeortotransferitsCAM
databasetoshopfloorforproductionpurpose.
TranslatedatabasebetweenCAD/CAMsystemusing
graphicsstandardsuchasIGES,STEP
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38. SoftwareModules ModulesFunction Examples
Operatingsystem Utility and systemcommands File manipulation,
managing directoriesetc
GeometricModule Geometric modelling,editing,
manipulation, drafting
documentation
Model creation, cleanup,
plottingetc.
Applicationmodule Use model for designand
manufacturing purpose.
Analysis, Animation, NC
simulation
FEA, tolerances analysisetc
Programmingmodule Customized system tofit
certain design and
manufacturingtask
Autolisp,Macros
Communication
module
Integration CAD/CAM
system other computer
system andmanufacturing
facility
IGES,STEP
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39. Software Package ofModeling
TherearenumberofCADpackagesavailablefor
modeling are asfollows
AutoCAD
Pro-E
Uni graphics
CATIA
Solidworks
Hypermesh
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40. Characteristics of CADpackage
According to Newman and Sproull, Any graphic package
should have the belowcharacteristics,
1)Simplicity
2)Consistency
3)Completeness
4)Robustness
5)Performance
6)Economy
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41. Features of CADpackage
1.Geometric modeling features
2.Editing or Manipulationfeatures
3.Display controlfeatures
4.Draftingfeatures
5.Programming facilities
6.Analysis features
7.Connectingfeatures
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42. 1.Geometric ModelingFeatures
A)Features to aid geometric constructionmethods
Cartesian and polarcoordinates
Absolute and incremental dimensions
Units
B)2D analyticalfeatures
Points, Lines, Arcs, Circles, andSplines
C)3D wireframe modelingfeatures
3Dlines,3Dfaces,Ruledsurfaces,RotationalsweepandTapered
sweep
D)Surface modelingfeatures
E)Solid modelingfeatures
F)Assemblyfeatures
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43. 2.Editing or ManipulationFeatures
a)Transformationfeatures
Translate, Rotate, Scale, Mirror, copy,etc.,
b)To alter the existingdrawings
Stretching, Trimming, Undo, Delete, Erase,etc.,
c)Symbolsfeatures
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44. 3.Display ControlFeatures
Toprovideauserfriendlyinterfacewitheffectivevisuals
characteristics suchas
a)Zoom to change the scale of display of theobject
b)Pan to move the object on screen without changing thescale
c)Hidden toremovethehidden lines orsurfacesforviewingthe
geometry
d)Animation to display the number of images in sequence to copy
the actualmotion
e)Shading to show the 3D view of the image on screen and shade as
it appears on theimage
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45. 4.DraftingFeatures
Ithaveuseddifferentdimensiontypessuchaslinear,angular,
radius, circular, baseline and limit dimensionsetc.
Sectioningfeaturestogetabettervisualizationofthemodelor
object.
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46. 5.ProgrammingFeatures
Integrationwithsmallprogramsdevelopedinprogramming
language to avoid repetitivetasks.
Programming facility allows the user to program specifically for
anapplication
Programs help the user to input the least amount of information for
any requireddesign
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47. 6.AnalysisFeatures
Inmodellingfeatures,thepackageshouldhavemanyanalysis
features and facilities such asinclude,
Calculation ofarea
Calculation ofvolume
Calculation ofmass
Calculation of moment ofinertia
Calculation of Centre ofgravity
In FEA, the developed model is converted into finite element mesh
and the all the required data are calculated foranalysis.
Animation facility is also used to see the assembly of themodel
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48. 7.ConnectivityFeatures
Themodelorobjectsogeneratedinanyofthepackagemustbe
capableenoughtobeusedasainputtoanyotheranalysispackage
withorwithoutconverter.
Thedata(graphics)lossesisminimumwhiletransferringthedata
fromonepackagetoanother.
Itshouldhaveverygooddatainterfacing(connectivity)withother
associatedmodules.
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49. 8.Drawing Features inCAD
Scalingtransformationusedtochange,increaseordecreasethe
sizeofanobjectwithoutaltertheshape.
Rotationthemovementofanobjectinsuchawaythatthe
distancebetweenacertainfixedpointandanygivenpointofthat
body.
Translationmovinganobjectacrossthescreenfromoneposition
toanotherposition.
Editingchangesthepropertiesofaspecificobjectbytheediting
commandsofpackage.
ZoomMagnifyingaportionofcurrentdrawingonthescreen.
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50. Requirement ofCAD
REASONS FOR IMPLEMENTING CAD
To increase the productivity of thedesigner
To improve the Quality ofDesign
To improveDocumentation
To create a Database formanufacturing
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51. Application of CAD in AutomotiveDevelopment
CAD is one of the central disciplines in modernautomotive
development.
The efficient CAD models provides the basis for a broadfield
ofconcernedengineeringprocesses. (BOM geometrical and
functional interactions, production-related informationetc.)
Using the CAD model pre-calculation of vehicle structures,
durability and acoustic optimization etc. done by without
physicaltests
The provision of CAD data support in the determinationof
cost relatedaspects.
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52. 3DModeling
3D modeling is the process of developing a
mathematical representation of any surfaceof
an object in three dimensions viaspecialized
software.
3D Modelingapproach
Primitive
Feature
Sketching
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53. Primitiveapproach
The primitives approach views a solid model as a combinationof
simple. generic, and standard shapes that can becombined
Primitives include a block (box), cylinder, sphere, cone,wedge,
andtorus
These primitives are combined via the Boolean operationsunion,
subtraction, andintersection.
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54. •Primitivemodeling
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55. Features basedapproach
It similar to primitive approach, It replaceprimitive
with a feature and embed Boolean operation in the
featuredefinition
Each feature can be independent or linked toother
feature
Thegeometryofeachfeatureis
Controlbymodifiableconstraints
anddimensions
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56. Sketchingapproach
Users can express their intent by sketching 2D shapethen
various feature will beappliedtogenerator 3Dmodel.
It allows CAD designers to create much more elaborate
and more general features starting from asketch
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57. Type of Geometricmodel
2 ½ Dmodel
2½ D models are the ones that have uniform cross section and thickness ina
direction perpendicular to the plane of the crosssection.
Extrusion: ConstantcrosssectionandThicknessinadirectionperpendicularto
the plan of crosssection
Axisymmetric : Constant cross section about the axis ofrevolution
Composite : It is combination of extrusion andaxisymmetric
60
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58. 3DObject
3D models are the ones that do not have a uniform cross
section and/or do not have a constantthickness.
Such models usually require more than one sketchin
different sketch planes anduse
advanced commands such as sweep andloft.
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59. •3D Geometric ModelingTechniques
There are basic the three types of 3D geometric modeling techniques,
WireframeModel
A wireframe representation is a 3-D line drawing of an object showingonly
the edges without any side surface inbetween.
A frame constructed from thin wires representing the edges andprojected
lines andcurves
Contains information about the location of all points and edges inspace
coordinate
Each vertex is defined by x,y,zcoordinate
Edges are defined by pair ofvertices
Faces are defined
by three or moreedges
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60. •Advantage WireframeModel
Can quickly and efficiently conveyinformationthanmulti
viewdrawings.
The only lines seen are the intersections ofsurfaces.
Can be used for finite elementanalysis.
Can be used as input for CNC machines to generatesimple
parts.
Contain most of the informationneededtocreatesurface,
solid and higher ordermodels
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61. Limitation WireframeModel
Ambiguities present in the wireframemodel
Volume or surfaces of object notdefined
Forcomplexitems,theresultcanbeajumble of lines
thatisimpossible todetermine
Limited ability for checking interference betweenmating
parts.
No ability to determine computationally information suchas
theline of intersect between two faces ofintersecting
models.
Cannot be used to calculate dynamicproperties
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63. SurfaceModel
Asurfacemodelrepresenttheskinof anobject,theseskinshave
no thickness ormaterial
Surface model define the surface features, as well as edgesof
object
Mathematical function describes the path of acurve
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64. Advantage of SurfaceModel
Eliminate ambiguity like wireframemodel
Can use for CNC machining mold and die design,FEA
Typical applications of 3D CAD surface modeling includebody
design inautomotiveandaeronautic engineering and the
representation of complexgeometries
Surface properties such as roughness, color and reflectivity canbe
assigned anddemonstrated
Volumetric properties of an object can be easilyobtained
Limitation of SurfaceModel
Surface models provide no information about the inside of anobject
Complicated computation, depending on the number ofsurfaces
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65. Solid (Volume)Model
Solidenableacompleteandcompactgeometricalrepresentation
ofobjectinavirtualenvironment
Solidmodelsarecapableofdefiningclosingconditions,
inside/outsideinformationandgeometricalconsistency
specifications.
It able to define material properties supports the realizationof
several physicalsimulations
improves the quality of design improvesvisualization
Simulation under real-life conditions and less expensivethan
building a physicalmodel
Can be used for presentations andmarketing
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66. ModelingStrategies
In CAD software one type of 3D model is possible to create byN
number of waybut,bestmodeling strategies is a sequences of
through about the easiest, fastest way tocreategeometricmodel.
The guidelines of modeling strategies arebellow
1.Determine model type andsubtype.
2.Observe geometric characteristics ofmodel
3.Choose model orientation in 3Dspace
4.Choose model origin
5.Decide on other geometricdetails
6.Avoid unnecessarycalculations
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67. VRML(Virtual Reality ModelingLanguage)
Enable to displace CAD model without CADsoftware
Able to manipulate (rotation/move/zoom) the CADmodel
VRML (Virtual Reality Modeling Language), originally before 1995known
astheVirtual Reality Markup Language is a standard file format for
representing3Dmodelin the World WideWeb
VRML is a text file format where, e.g., vertices and edges for a 3Dpolygon
canbe
specified along with the surface color, shininess, transparency, and soon
Very useful for marketing engineer, client, customersetc.
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68. 71
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