CATIA基础教程6

REFERENCEELEMENTS64IfyourREFERENCEELEMENTStoolbarisnotinviewandnothidden,youcanretrieveitfromthetoolbarsmenuseenhere.65REFERENCEELEMENTSplayanimportantpartinanysolidmodeling.Withoutthem,youcanonlydoworktotheoutermostsurfacesofthepart,whichmaynotalwaysbepracticalorinvolvealotofpre-drawplanning.66Tocarveastepintoyourpartwithoutsettingareferenceplane,youareverylimitedastowhereyoucanputit.Youmustfirstpickapartfacethatyouaregoingtoworkon.Thiswillunfortunatelybewhereyourstepwillbegin,likeitornot,withoutsettingaplane.67Onceyouhaveenteredsketcher,youwilldrawtheshapeofthestepthatwillbeinyourpart.Noticeinthisexamplethatpartofthestepshapeextendsbeyondthepart.Thebitofshapethatisnotpartofthestepisofnoconsequenceatthispoint.Thismethodisthequickestandmostconvenientwayofcarvingoutastep…butkeepinmindthatifACCURACYisimportant,youmustconsiderhowmuchofthestepisoverhangingthepartinyouoverallcalculations.overhang68Oncebackin3Dmode,youcanseeSketch2inrelationtothepart.YoucannowPOCKEToutthisshapefromoneendtotheother,andanywhereinbetween.Wewillpocketit1inch.69AtthispointwehavehighlightedSketch2andpickedPocketfromtheDressUptoolbar.ThePocketDefinitiondialogboxpopsupforyoutoentertheinitialdepthofpocket.DepthofpocketNoticeinthedefinitionboxyoucanalso“mirror”thepocketforittogobothwaysor“reverse”it.Mirror(pick)70Herewehavethepartwiththepocketcutintoitmakingastep.Thisisconvenientifyouareonlyworkingonthefacesofthepart,butwhatifyouneedastepinthemiddleofoneedge?71Letstakethesameshapeandcarveastepintothemiddleofthefrontedge,leavingmaterialonbothsides.Forthiswearegoingtohavetodothesamethingsasbefore,onlyfirstwemustaddaREFERENCEELEMENT.72AReferenceElementisanotherplaneyoucanuseasareferenceforotherdrawingbitsonyourpart.Todothiswefirstpickthefacewewishtoreferencefrom,pickPLANEfromtheReferencetoolbar,andinthePlaneDefinitiondialogboxwewillenterhowfartheplaneshouldbefromthefaceweinitiallypicked.planeEnteroffset73Hereweseetheplanesetintoplaceandreadytobeusedasareferenceelement.74Tousethereferenceelement,firstpickit(itwillhighlightorange)andthenpicksketcher.NoticeontheTREEthat‘OpenBody’appearsonitsownlimbwith‘plane1’attachedtoit.75Hereinsketcheritisdifficulttoknowwhichplaneyouaredrawingon.Ifyouforget,checkthetree.Hereweseethatthesketchwearedoingatthemomentisbeingdoneinplane2,aswewished.Otherthanthat,youproceedexactlyaswedidtheotherstep.76Backin3Dweseethatourshapeisexactlyinthemiddleofthepart,asweexpected.77Fromherewedoexactlyaswedidwiththeotherstep.Wehighlighttheshapeandchoosethepocketicon.Giveitdepthinthedialogboxandmaybeevenmirrorit(aswedidhere)forextrasize.78