国家制造业信息化AUTOCAD认证考试样题

辽宁石油化工大学机械工程学院计算机绘图双语教学讲义No13TangXiaochuLiJingChapter10UsingBlockandExternalReferences10.1OverviewAutoCADprovidesseveralfeaturestohelpyoumanageobjectsinyourdrawings.Withblocksyoucanorganizeandmanipulatemanyobjectsasonecomponent.Youcanalsoassociateitemsofinformationwiththeblocksinyourdrawings-forexample,partnumbersandprices-byattachingattributes.Specificationsheetsorbillsofmaterialscanbecreatedusingthisinformation.YoucanattachoroverlayentiredrawingsinyourcurrentdrawingbyusingAutoCADexternalreferences,orxrefs.Whenyouopenadrawingthatcontainsxrefs,anychangesthathavebeenmadeinthereferenceddrawingappearinthecurrentdrawing.10.2WorkingwithBlocksAblockisacollectionofobjectsyoucanassociatetogethertoformasingleobject,orblockdefinition.Youcaninsert,scale,androtateablockinadrawing.Youcanexplodeablockintoitscomponentobjects,modifythem,andredefinetheblock.AutoCADupdatesallcurrentandfutureinstancesofthatblockbasedontheblockdefinition.Blocksstreamlinethedrawingprocess.Forexample,youcanuseblockstoBuildastandardlibraryoffrequentlyusedsymbols,components,orstandardparts.Youcaninsertthesameblocknumeroustimesinsteadofre-creatingthedrawingelementseachtime.Revisedrawingsefficientlybyinserting,relocating,andcopyingblocksascomponentsratherthanindividualgeometricobjects.Savediskspacebystoringallreferencestothesameblockasoneblockdefinitioninthedrawingdatabase.Forinformationabouthowtocreateablock,seeDefiningBlocks.Whenyouinsertablockinyourdrawing,youarecreatingablockinstance.Eachtimeyouinsertablockinstance,youassignascalefactorandrotationangletotheinsertedblock.Youcanalsoscaleablockinstanceusingdifferentvaluesinanycoordinate(X,Y,Z)direction.Blocksmakeitpossibleforyoutoorganizeyourdrawingtasksinasystematicway,sothatyoucansetup,redesign,andsorttheobjectsinyourdrawingsandtheinformationassociatedwiththem.DefiningBlocks辽宁石油化工大学机械工程学院计算机绘图双语教学讲义No13TangXiaochuLiJingYoucangroupobjectstocreateblockdefinitionsinthecurrentdrawing,oryoucansavetheblockasaseparatedrawingfile.Whenyoudefineablock,youspecifythebasepoint,theobjectstogroup,andwhethertoretainordeletetheobjectsorconvertthemtoablockinthecurrentdrawing.YoucanalsoenteratextdescriptionandspecifyaniconusedtohelpidentifytheblockdefinitioninAutoCADDesignCenter.Blockdefinitionsareoneofmanynongraphicalobjectssavedinadrawing.SeeWorkingwithNamedObjects.Tocreateablockdefinition1FromtheDrawmenu,chooseBlockMake.2IntheBlockDefinitiondialogbox,enteranamefortheblock.3UnderObjects,choosetheSelectObjectsbuttontousethepointingdevicetoselectobjectsfortheblockdefinition.Thedialogboxclosestemporarilywhileyouselectobjectsfortheblock.PressENTERwhenyouaredoneselectingblocks.Thedialogboxreopens.4Ifyouwanttocreateaselectionset,usetheQuickSelectbuttontocreateordefineafilterforyourselectionset.SeeFilteringSelectionSets.5UnderObjects,specifywhethertoretain,converttoablock,ordeletetheselectedobjects.Retain:Keepsselectedobjectsinthecurrentdrawing,intheiroriginalstate.ConverttoBlock:Replacesselectedobjectswithaninstanceoftheblock.Delete:Removesselectedobjectsaftertheblockisdefined.6UnderBasePoint,enterthecoordinatevaluesfortheinsertionbasepointorchoosetheSpecifyInsertionBasePointbuttontousethepointingdevice.7UnderDescription,entertexttohelpidentifytheblockforeasyretrieval.8UnderIcon,specifywhethertocreateaniconfromtheblockdefinition.Donotincludeanicon:Omitspreviewimagefromblockdefinition.Createiconfromblockgeometry:Savespreviewimagewiththeblockdefinition.9ChooseOK.Theblockdefinitionissavedinthecurrentdrawing.Tosaveablockorobjectasaseparatedrawingfile1AttheCommandprompt,enterwblock.2IntheWriteBlockdialogbox,specifyablockoranobjecttowriteoutasafile.Block:Specifiesablocktosaveasafile.EntireDrawing:Selectscurrentdrawingasablock.Object:Specifiesobjectstobesavedasafile.3UnderBlock,selectanamefromthelisttosaveasafile.辽宁石油化工大学机械工程学院计算机绘图双语教学讲义No13TangXiaochuLiJing4UnderBasePoint,usethePickPointbuttontodefinethebasepoint.5UnderObjects,usetheSelectobjectsbuttontoselecttheobjectfortheblockfile.6Enteranameforthenewfile.Ifablockisselected,WBLOCKautomaticallyusesthatblock'snameforthenewfile.7IntheInsertUnitslist,selectaninsertunittouseinAutoCADDesignCenter.8ChooseOK.Theblockdefinitionissavedasadrawingfile.InsertingBlocksYoucaninsertblocksorentiredrawingsintothecurrentdrawingwithINSERT.Whenyouinsertablockordrawing,youspecifytheinsertionpoint,scale,androtationangle.ThissectionexplainsinsertingblocksintoyourdrawingusingINSERT.SeeUsingAutoCADDesignCentertoInsertBlocks.Whenyouinsertanentiredrawingintoanotherdrawing,AutoCADtreatstheinserteddrawinglikeanyotherblockreference.Subsequentinsertionsreferencetheblockdefinition(whichcontainsthegeometricdescriptionoftheblock)withdifferentposition,scale,androtationsettings,asshowninthefollowingillustration.Ifyouchangetheoriginaldrawingafterinsertingit,thechangeshavenoeffectontheinsertedblock.Ifyouwanttheinsertedblocktoreflectthechangesyoumadetotheoriginaldrawing,youcanredefinetheblockbyreinsertingtheoriginaldrawing.Ifyouwanttoinsertadrawingbutyoudon'twantthefilenametobethesameastheblockname,youcaninser