课程教案Teaching Plan7.docx

课程教案Teaching Plan7.docx

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课程教案TeachingPlan7

TeachingPlan-7:

Sketch

LearningOutcomes

Onthecompletionofthisunityouwillbeabletocorrectlyusethefollowingskillsasfollows:

•Createasketch.

•Identifyconstraintscorrectly.

Assessment

Competencywillbeassessedbyoperationtasksthroughoutthissection.PleaseforwardthePracticalApplicationsManualtoyoursupervisorforassessmentoncompletionofoperationtasks.

Resources

PracticalApplications（Period:

2classesinclassroom）

《PracticalApplicationsofUGNX4.0（StudentGuide）》

Lesson7:

Sketching

Operation（Period:

2classesincomputertrainingroom）

《PracticalApplicationsManual》

Operation4:

Sketching

KeyPoint

Createandeditasketch,constraint

SketchingOverview

Asketchisacollectionoftwo-dimensionalgeometrywithinapart.Eachsketchisanamedcollectionof2Dcurvesandpointsresidingonaplanethatyouspecify.

Sketchertoolsletyoufullycaptureyourdesignintentthroughgeometricanddimensionalrelationshipsthatwerefertocollectivelyasconstraints.Useconstraintstocreateparameter-drivendesignsthatyoucanupdateeasilyandpredictably.

Whenthereisacommonlyusedshapethatvariesinsize,asketchcaneasilyaccommodatetheiterationsofthedesignbyeditingasingleconstraint.

Sketchesshouldbeusedasbasefeaturesofamodeliftheshapelendsitselftoextrudedorrevolvedgeometry.

SketchesandthePartNavigator

SketchescanbecreatedbychoosingtheSketchSectioniconincertainfeaturecreationdialogssuchasExtrudeandRevolve,choosingtheSketchicondirectlyintheFormFeaturetoolbar,orbychoosingInsert→Sketch.

CreatingaNewSketch

DefiningaSketchPlane

Whencreatingasketch,youfirstneedtodefinetheplaneonwhichtoplacethesketchcurves.But,youmustconsiderthestateofthemodel.

Aniconoptionbarshownbelowappearsintheupperleftcornerofthegraphicswindowandcontainsoptionstodefinethesketchplane.

NamingaSketch

Sinceauniquenameisrequiredforeachsketch,adefaultnamewillinitiallybeassignedwithanumericsuffix.Theformatofthedefaultnameis"SKETCH_###"where###isreplacedbythenextsequentialthreedigitnumberbeginningwith000（SKETCH_000,SKETCH_001,etc.）.Asketchnamemaybedefinedduringorafterthesketchhasbeencreatedbyclickingonthedefaultsketchname,typinginthenewnameandpressingEnter.

TheActiveSketch

Inanygivenparttheremaybenumeroussketchesofdifferentfeaturesatdifferentorientations.Whenusingthesketcher,onlyonesketchmaybeworkedonatatime.Thissketchiscalledtheactivesketch.Curvescreatedwhileasketchisactivebecomeassociatedwiththeactivesketch.Whenreturningtoasketchtoaddtoormodifyaprofile,thesketchmustbeactivated.Thereareafewwaystoactivateasketch:

•Double-clickingonasketchcurve.

•InthePartNavigatordouble-clickonthesketchfeaturenode.

•ChoosetheSketchiconandselectthedesiredsketchfromtheSketchNamepull-down.

Therearealsoafewwaystodeactivateanactivesketch:

•ChoosetheFinishSketchicon.

•ChooseSketch→FinishSketch.

•Activateadifferentsketch.

•ChooseSketch→Newandcreateanewsketch.

SketchCreationSteps

•Settheworklayerforthesketch.

•ChoosetheSketchicon.

•DefinethesketchplaneonaWCSplane（XC-YC,YC-ZC,orZC-XC）orcreateaDatumCSYSatabsolutecoordinates.

•Namethesketch.

•ChooseOK.

SketchCurves

SketchcurvesarecreatedviatheSketchCurvetoolbar.AscurvesarecreatedgeometricconstraintsareassignedtothecurvesrelativetotheInferConstraintsSettings.

1–Profile

2–Line

3–Arc

4–Circle

InferConstraintSettings

TheInferConstraintsSettingsdialogdetermineswhichconstraintsareautomaticallycreatedduringcurvecreation.ItisaccessedbychoosingtheInferConstraintSettingsiconfromtheConstraintstoolbarorTools→Constraints→InferConstraintSettings.

Asyoucreatethecurvesasymbolwillappearnearthecurvebeingcreatedtorepresenttheconstraintthatwillbeapplied,ifany.

LockingaConstraint

WhenaconstraintsymbolappearsduringcurvecreationyoumaylockinthatconstraintbypressingMB2.Forexample,ifyouarecreatingalineandtheparallelsymbolappears,pressMB2.Asyoumovethecursor,thenewlinethatisrubberbandingisdoingsoparalleltothereferencecurve.

SnapPointToolbar

TheSnapPointtoolbarcanbedisplayedwhencreatingmostofthecurvetypesinthesketchersothatyouhavemorecontrolovertheselectionoflocations.

WhentheSnapPointtoolbarisactive,regardlessofthepointtypesturnedon,cursorlocationisalwaysavailable.

ProfileTool

TheProfiletoolallowscreationofastringoflinesandarcswithouthavingtospecifyastartforeachcurveafterthefirstcurveiscreated.TheProfiletoolisturnedonbydefaultwhenyoufirstcreateasketchandcanbeaccessedbychoosingtheProfileiconontheSketchCurvetoolbar.

CreatingLines

LinecreationisaccessedbychoosingtheLineiconontheSketchCurvetoolbar.

Onceinlinecreation,theiconsintheupperleftcornerofthegraphicswindowprovidetwooptions:

CoordinateMode（bycursorlocationorkeyinginanXCandYCcoordinates）andParameterMode.

CreatingArcs

ArccreationisaccessedbychoosingtheArciconontheSketchCurvetoolbar.

Onceinarccreation,theiconsintheupperleftcornerofthegraphicswindowgiveyoutwosetsofoptions.Thefirstiscreationmethod,andthesecondisfortheCoordinate/ParameterMode.

Therearetwodifferentarccreationmethods:

Arcby3Points

•Locatethestart,locatetheend,andthenlocateapointonthearc.

•Locatethestart,enteraradiusvalueandpressEnter,locatetheendpoint,andthenmovethecursortopreviewandchoosewhichofthefourpossiblesolutionstocreate.

•Thesameastheprevious,butentertheradiusvalueafterlocatingtheendpoint,butbeforethepointonarc.

ArcbyCenterandEndPoints

•Locatethecenter,locatethestartpoint,andlocatetheendpoint.（Thestartpointlocationdeterminestheradius.）

•Locatethecenter,locatethestartpoint,enteraradiusvalueandpressEnter,locatetheendpoint.

•Locatethecenter,enterradiusandsweepanglevaluesandpressEnter,locatethestartofthesweep,andspecifythedirectionforthesweep.

CreatingCircles

CirclecreationisaccessedbychoosingtheCircleiconontheSketchCurvetoolbar.

Onceincirclecreation,theiconsintheupperleftcornerofthegraphicswindowprovidetwosetsofoptions.Thefirstiscreationmethod,andthesecondisfortheCoordinate/ParameterMode.

Therearetwodifferentcirclecreationoptions:

CirclebyCenterandDiameter

•Locatethecenter,andthenlocateapointonthecircumferenceofthecircle.

•Locatethecenter,enteraDiameter,andpressEnter.Thecircleiscreated.Youaretheninmultiplecirclecreationmode-justindicateanotherlocationforacirclecenter.

•Locatethecenter,dragtheradiusuntilyougetthesizeyouwant.PressEnter.Thecircleiscreated,andyouareinmultiplecirclecreationmode.Indicateanothercenter.

Circleby3Points

•Locatethreepointsonthecircumferenceofthecircle.

•Locatetwopointsonthecircumferenceofthecircle,enteraradiusvalueandpressEnter,thenchoosewhichofthetwooptionsyouwantbycursorlocation.

CreatingFillets

FilletcreationisaccessedbychoosingtheFilleticonontheSketchCurvetoolbar.

Onceinfilletcreation,iconoptionsappearintheupperleftcornerofthegraphicswindow.TheTrimInputsoption

（1）determineswhetherornottheoriginalcurvesaretrimmed.TheDeleteThirdCurveoption

（2）determineswhetherthemiddlecurveisdeletedinathree-curvefillet.TheCreateAlternateFilletoption（3）willproduceacomplementarysolutionforthefillet（e.g.a270degreearcinsteadofthedefault90degreearc）.

Youcancreatefilletsbetweenlines,arcsorconics.Youcanalsocreateafilletbetweentwoparallellines.

ThereareseveralwaystocreateFillets:

•Selecttwocurveswithasingleselection（attheirintersection）,andthendragthesizeandquadrant.

•Selecttwocurvesindividually,anddragthesizeandquadrant.

•Selectonecurve,enteraradiusvalue,andselectthesecondcurve.

•Selecttwocurvesindividually,enteraradiusvalue,andtheindicatethedesiredquadrant.

•Drag（withMB1）acrossthetwocurvesyouwanttofillet.Thesizeofthefilletisdeterminedbywherethecurvesareselected.

TrimmingandExtendingCurves

QuickTrim

Thisoptionwillallowyoutotrimanycurvetotheclosestcurveinthesketchandpreviewtheresultsinpreselectioncolor.

Youcantrimmultiplecurvesatonetime,byusingthe"crayon"selectmethod.

HolddownMB1anddragacrosstheportionofcurvesyouwanttotrimaway.

Youcanselectaspecificcurvetotrimto,byusingCtrl-selecttoselectthedesiredboundarycurve.Morethanoneboundingcurvecanbeselectedusingthismethod.

Whenacurveistrimmed,appropriateconstraintsareautomaticallycreated.Inthepreviousexample,twoPointonCurveconstraintsandoneCollinearconstraintareadded.Ifoneoftheboundarycurvesislatertrimmedtotheline,thePointonCurveconstraintwouldchangetoCoincident.

Ifyoutrimanarctoalinethatistangent,thetangencyconstraintisretained.

QuickExtend

Thisoptionwillextendlines,arcsandconicstotheclosestcurveinthesketch.Thesystemwillpreviewtheresultsinthepreselectioncolor.

Thecurvebeingextendedmustextendtoanactualintersectionwiththeboundarycurve.

Youcanextendmultiplecurvesat