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攀枝花学院本科毕业设计（论文）外语文翻译攀枝花学院本科毕业设计（论文）外语文翻译1外语文献翻译原文341CADHARDWARECOMPUTERSTHEREARETWOMAJORTYPESOFHARDWAREUSEDINACADSYSTEMCOMPUTERANDINPUT/OUTPUTI/ODEVICESINTHEEARLYDAYSOFCADSOMECOMMERCIALCADSYSTEMSUSEDPROPRIETARYCOMPUTERSTODAY,NEARLYALLCADSOFTWARERUNSONAGENERALPURPOSECOMPUTERDEPENDINGONTHECOMPLEXITYOFTHECADPACKAGE,ITMAYREQUIREAMAINFRAMECOMPUTER,AMINICOMPUTER,ORSIMPLYAMICROCOMPUTERINGENERAL,THEMOREFUNCTIONALITIESACADSYSTEMPROVIDES,THEMOREPOWERFULTHECOMPUTERNEEDEDTHREEDIMENSIONALSOLIDMODELERSREQUIREMUCHMORECOMPUTINGTHANDOTWODIMENSIONALDRAFTINGSYSTEMS；THUS,THEYNEEDMOREPOWERFULCOMPUTERSSYSTEMSTHATINTEGRATEENGINEERINGANALYSISORSIMULATIONPACKAGESGENERALLYAREMORECOMPUTATIONINTENSIVEAPOWERFULCOMPUTERNOTONLYSPEEDSUPTHERESPONSEOFACADSYSTEM,BUTALSOCANSUPPORTMULTIPLEUSERSWITHOUTSIGNIFICANTPERFORMANCEDEGRADATIONSEVERALOTHERPARAMETERSANDCOMPONENTSCONCERNINGTHECOMPUTERALSOHAVETOBECONSIDEREDCADHARDWARERANDOMACCESSMEMORYRAMCAPACITYPERMANENTDISKSTORAGECAPACITYSPECIALGRAPHICSACCELERATORTAPEBACKUPSRAMISTHEACTUALPHYSICALMEMORYVSVIRTUALMEMORYOFACOMPUTERASMALLMEMORYCAPACITYMEANSSLOWPROCESSINGDUETOFREQUENTSWAPPINGBETWEENTHEPHYSICALMEMORYANDTHEVIRTUALMEMORYONDISKBECAUSECADISEXTREMELYSTORAGEDEMANDING,DISKCAPACITYISIMPORTANTSMALLDISKCAPACITYLIMITSTHESYSTEMTOTHESTORAGEOFONLYAFEWDRAWINGSCADISGRAPHICSBASEDANDREQUIRESTREMENDOUSDATAPROCESSINGAGRAPHICSACCELERATORCANDRASTICALLYINCREASETHEPERFORMANCEOFTHESYSTEMANOTHERCOMPONENT,THEHARDDISK,ISTYPICALLYTHEMAJORCOSTOFACOMPUTERSYSTEMTHEREFORE,ITISNOTCOSTJUSTIFIABLETOSTOREALLDRAWINGSONLINEONDISKMAGNETICTAPEISSTILLTHEMOSTECONOMICALMEDIUMTOUSEFOROFFLINEDATASTORAGEITISNECESSARYFORACADSYSTEMTOHAVEATAPEBACKUPSUBSYSTEMCURRENTLY,ALLLEVELSOFCOMPUTERSAREUSEDINCADSYSTEMSPERSONALCOMPUTERSAREUSEDINLOWCOST,2DDRAFTINGAPPLICATIONS,ANDWITHTHENEWPOWEROFTHESECOMPUTERS,HEYAREALSOBEINGUSEDFORSOME3DSOLIDMODELINGAPPLICATIONSENGINEERINGWORKSTATIONSHAVEBEENTHEMAINSTAYINCAD,ANDAREUSUALLYASINGLEUSERCADWORKSTATIONINANETWORKMINICOMPUTERSAREUSEDINMULTIUSERCADSYSTEMSMAINFRAMESAREUSEDFORLARGEMULTIUSERCADSYSTEMSTOSUPPORTREALTIMESIMULATIONANDENGINEERINGANALYSISSOMETIMES,INALARGECORPORATION,ALLLEVELS攀枝花学院本科毕业设计（论文）外语文翻译2OFCADSYSTEMSAREIMPLEMENTEDALLTHESESYSTEMSARELINKEDTOGETHERTHROUGHAHIERARCHICALCOMPUTERNETWORK342INPUTOUTPUTI/ODEVICESFIGURE37SHOWSTHETYPICALI/ODEVICESUSEDINACADSYSTEMINPUTDEVICESAREGENERALLYUSEDTOTRANSFERINFORMATIONFROMAHUMANORSTORAGEMEDIUMTOACOMPUTERWHERE”CADFUNCTIONS”ARECARRIEDOUTAKEYBOARDISTHESTANDARDINPUTDEVICEUSEDTOTRANSMITALPHANUMERICDATATOTHESYSTEMFUNCTIONKEYPADSAREALSOUSEDTOMAKEINPUTEASIERJOYSTICKS,TRACKBALLS,ANDMOUSSEAREALSOUSEDTOMANIPULATEACURSORTHEYCANBEUSEDTOPOSITIONTHEGRAPHICCURSOREGCROSSHAIRONAMONITORANDFEEDBACKTHELOCATIONOFANOBJECTONTHEMONITORTOTHECOMPUTERUSINGTHESEDEVICESALLOWSANOPERATORTOADDRESSTERMINALLOCATIONSTOINTERACTIVELYINREACHINGANACCURATEPOSITIONMOUSESHAVEBEENUSEDEXTENSIVELYWITHWINDOWSANDPULLDOWNMENUSTHEYAREEASYTOUSEFORPOINTING；HOWEVER,USINGAMOUSETOTRACEACURVEISNOTANEASYTASKTHEREARETHREEBASICAPPROACHESTOINPUTANEXISTINGDRAWING；1MODELTHEOBJECTONADRAWING,2DIGITIZETHEDRAWING,OR3SCANTHEOBJECTDIGITIZINGISUSUALLYMUCHEASIERTHANMODELINGADIGITIZERISADEVICETHATTRANSLATESTHEXYLOCATIONSONADRAWINGTHANMODELINGADIGITIZERISADEVICETHATTRANSLATESTHEXYLOCATIONSONADRAWINGINTOADIGITALANDFEEDSTHATSIGNALTOACOMPUTERGRAPHICSSCANNERSSCANADRAWINGANDCONVERTITTOACADSYSTEMREADABLEFORMATSOMESCANNERSHAVEBUILTINCHARACTERRECOGNITIONSOFTWARETHATCANCONVERTCHARACTERSONPAPERINTOASCIICODESANOTHERINPUTDEVICEISASKETCHPADCALLEDAGRAPHICSTABLETAGRAPHICSTABLETISASPECIALFLATSURFACEONWHICHAUSERDRAWSWITHASTYLUSTHELOCATIONOFTHESTYLUSISSENTTOTHECOMPUTERTHETABLETISANABSOLUTECOORDINATEDEVICEITISEASYTOIMPLEMENTOVERLAYMENUSONTHETABLETANDPULLDOWNMENUSONTHESCREENTOIMPROVETHEOPERATIONCURRENTLYTHETABLETISTHEMOSTPOPULARINPUTDEVICEUSEDINCADOTHERTHANTHEKEYBOARDTHESTANDARDOUTPUTDEVICEFORCADISAMONITORDISPLAYMODERNMONITORDISPLAYSARERASTERSCANDISPLAYMONITORSSIMILARTOATVMONITOR,ANELECTRONGUNSONYTRINITRONUSESTHREEGUNSFORTHREEBASICCOLORSSENDSANELECTRONICBEAMTOTHEFRONTOFTHEMONITOREASYDISPLAYDOTISCALLEDAPIXELPICTUREELEMENTFORCOLORDISPLAYS,EACHPIXELISREPRESENTEDBYTHREECLOSELYLOCATEDDOTSWITHRED,GREEN,ANDBLUECOLORSTHEELECTRONICBEAMSELECTSTHECOLORELEMENTSANDTHEINTENSITYOFEACHCOLORELEMENTTHERESOLUTIONOFTHEMONITORISDETERMINEDBYTHENUMBEROFDIFFERENTCOLORSORGRAYSCALESDISPLAYABLEATEACHPIXEL,USUALLYMEASUREDINBITS,A1BITDISPLAYCANTURNEACHPIXELEITHERONOROFFAGRAYSCALEHASATLEASTV2BITSA1BITDISPLAYCANTURNEACHPIXELEITHERONOROFFAGRAYSCALEHASATLEAST2BITSWHICHALLOWTHREELIGHTINTENSITIESPLUSANOFF22USUALLY,DISPLAYSARE4BITS16COLORS,8BITS256COLORS,16BITSTHOUSANDSOFCOLORS,AND24BITSMILLIONSOFCOLORSTHEELECTRONICBEAMSWEEPSTHESCREENFROMTHETOPTOTHEBOTTOMLINEBYLINEBECAUSETHEDOTISLITFORONLYAVERYSHORTPERIODOFTIME,THESWEEPMUSTBEDONEVERYQUICKLYINORDERNOTTOHAVEAFLICKERINGIMAGETHEREFRESHRATEISAMEASUREOFHOWMANYTIMESTHEMONITORISREDRAWNINONESECOND攀枝花学院本科毕业设计（论文）外语文翻译3THECOMPUTERDOESNOTDRAWDIRECTLYONTHEMONITORCONNECTINGTHECOMPUTERTOTHEMONITORISUSUALLYARGBRED,GREEN,BLUECABLETHREESEPARATESIGNALLINESARECONNECTEDONTHEGRAPHICSBOARDINTHECOMPUTERARECIRCUITSTOGENERATETHEANALOGSIGNALSREQUIREDTODRIVETHEMONITORTHEREISALSOAFRAMEBUFFERTHATSERVESASMEMORYTOSTORETHEIMAGEEACHPIXELONTHESCREENHASACORRESPONDINGADDRESSINTHEFRAMEBUFFERTHEDATAINTHEFRAMEBUFFERARECONVERTEDINTOTHEAPPROPRIATEANALOGSIGNALANDSENTTOTHEMONITORATTHEREFRESHRATESEPARATELY,THECOMPUTERWRITESDIRECTLYTOTHEFRAMEBUFFERTHEIMAGEITINTENDSTODRAWTHEGREATERTHEDISPLAYSIZEANDNUMBEROFCOLORS,THEMOREFRAMEBUFFERISNEEDEDTHEFRAMEBUFFERONTHEGRAPHICSBOARDISMADEOFRANDOMACCESSMEMORYRAMTHECALCULATORLENDSUPPORTTOESTOPAINTTHESOFTWAREAUTOCADTOMAKEUSCANBEWITHTHESKETCHTHATTHEASTONISHINGSPEEDDRAWTHEENGINEERINGSKETCHORMACHINESKETCHANDOTHERWITHACCURACYTOSOPHISTICATETHECALCULATORPAINTSTOPAINTTHEDIFFERENTPLACE,ONEOFTHEMWITHHANDICRAFTTHEPAINTINGSWITHOUTTHEDIAGRAMDIVIDEASTEPPROCEEDOF,BECAUSEOFBUTWOULDSOMETIMESAPPEARTHETRADITIONALHANDICRAFTTHEPAINTINGHOURTHEPROBLEMOFTHEIMPOSSIBLEEMERGENCEGENERALCIRCUMSTANCEBOTTOM,USAGETHEAUTOCADPROCEEDSPAINTING,CONTROLTHEPRECISIONPAINTINGANDNOTTHATDIFFICULT,BUTWANTACCURATETHENNEEDTHECERTAINTECHNIQUEOUTTHEDIAGRAMUSUALLYPAINTOROUTSINGDIAGRAMTOHAVENOTONEEDTOCHANGETOMEASURETOAUTOCADSYSTEMWORTHMAKETHEMODIFICATIONWITHESTABLISH,TAKEITSTHEPROVINCEWORTHCANNORMALWORK,BUTHAVETHESPECIALREQUEST,MUSTMODIFYTHERELATEDSYSTEMTOCHANGEMEASURE；TOOSOMETIMESTHEREQUESTOFTHEDIAGRAMPAPERWITHMAKETHEDIAGRAMSWAYOFDOINGTHEANTINOMY,ANDBETOADOPTTHETOMAKETHEDIAGRAMMETHODTOCANTATTAINTHEREQUESTOFTHEDIAGRAMPAPER,WILLADOPTSOMETECHNIQUEIQUESTOMODIFYTHERELATEDSYSTEMTOCHANGETOMEASURE,ANDCANMAKETHECALCULATORDRAWTOATTAINTHEREQUESTOFTHEDIAGRAMPAPERWITHOUTPUTSSKETCHAUTOCADLINETYPEESTABLISHINGOFCOMPARISONATTEACHINGOFPROCESSINSIDEWOULDUSUALLYRUNINTOWHATTHISKINDOFCIRCUMSTANCE,WHILEESTABLISHINGDIAGRAMLAYER,CLEARLYESTABLISHEDTHEPOINTLINEATIONED,ANDCONSEQUENTLYOUTPUTTOHOWEVERINVESTIGATEITSREASONFORTHESOLIDLINED,ANDISUSUALLYBECAUSEOFTHELINETYPEDTHEESTABLISHINGOFCOMPARISONISNOTAPPROPRIATEANDCAUSABLESHOULDYOUSOESTABLISHTHECOMPARISONOFWHATKINDOFLINETYPEHOWTOUSETHELINETYPETHECOMPARISONINTHEPAINTINGUSAGEAUTOCADPAINTING,BESIDESCONTINUOUSLINETYPECONTINUOUS,THEOTHERLINETYPEISALLFROMTHESOLIDLINESEGMENT,BLANKSEGMENT,POINTSERIESFORORTEXTTHISCONSTITUTINGONLINETYPEDEFINITIONDOCUMENTTHEINSIDEHAVEALREADYDEFINEDTHESELINETYPESTHESEGMENTSSTANDARDLENGTH,ANDSHOWONHELDTHEACTORATPRINTTHEMACHINE\PAINTINGOUTPUT,EACHLENGTHANDEXPORTATIONCOMPARISONWITHLINETYPECOMPARISONDIRECTPROPORTIONWHENSHOWORPRINT,THEPAINTINGBOUNDARYTHATCUSTOMERTHATREQUEST,THISHOURESTABLISHISOUTOFACCORDANCEWITHTHEPAINTINGBOUNDARYOFTHEPROVINCEDIFFERENCEBIG,ONHELDTHEACTSHOWORPAINTOUTPUTSLINETYPEWOULDMATCHTHEENGINEERINGGRAPHICSTOWILLPASSTHECHANGESLINETYPECOMPARISONTHESYSTEMTHEMETHODTHATCHANGETHEDEAL,ENLARGEOR
