AutoCAD英文教程专业知识讲座

LectureTwo4Creating2DObjects

1

ModifyingObjects2

WorkwithLayers35

DrawingGeometricObjects

CreateaDrawingTemplateFile

ControlScreenDisplay6第1页1.Creating2DObjectsYoucancreatearangeof2Dobjects,fromsimplelinesandcirclestosplinecurves,andellipses.Ingeneral,youdrawobjectsbyspecifyingpointswiththepointingdevice,byenteringcoordinatevaluesonthecommandlineorbyDrawtoolbar.第2页1.1DrawingLinearObjectsDrawLines

Inasimplelinewithconnectedsegments,eachsegmentisaseparatelineobject.DrawPolylines

Apolylineisaconnectedsequenceoflinesegmentscreatedasasingleobject.Youcancreatestraightlinesegments,arcsegments,oracombinationofthetwo.DrawRectanglesandPolygons

Youcancreaterectanglesandregularpolygonsquickly.Creatingpolygonsisasimplewaytodrawequilateraltriangles,squares,pentagons,hexagons,andsoon.DrawMultiple-LineObjects

Multilinesarecomposedof1to16parallellines,calledelements.第3页1.1.1DrawingPolylines

Apolylineisaconnectedsequenceoflinesegmentscreatedasasingleobject.Youcancreatestraightlinesegments,arcsegments,oracombinationofthetwo.Multisegmentedlinesprovideeditingcapabilitiesunavailableforsinglelines.Forexample,youcanadjusttheirwidthandcurvature.Afteryou'vecreatedapolyline,youcanedititwithPEDIToruseEXPLODEtoconvertittoindividuallineandarcsegments.第4页1.1.2DrawingRectangles

UseRECTANGtocreateclosedpolylinesinarectangularshape.Youcanspecifythelength,width,area,androtationparameters.Youcanalsocontrolthetypeofcornersontherectangle—fillet,chamfer,orsquare.

Chamfer=5x5Fillet=10.0000Chamfer=0Fillet=0Width=5Rectanglemodes:

Rtation=31Area=1000Length=50Dimensions:Length=100Width=40第5页1.1.3DrawingPolygons

UsePOLYGONtocreateclosedpolylineswithbetween3and1,024equal-lengthsides.Thefollowingillustrationsshowpolygonscreatedusingthreemethods.Ineachcase,twopointsarespecified.

Enternumberofsides<current>:Enteravaluebetween3and1024orpressENTERSpecifycenterofpolygonor[Edge]:Specifyapoint(1)orentere第6页

1.2DrawCurvedObjectsCurvedobjectsarearcs,circles,polylinearcs,donuts,ellipses,andsplines.1.2.1DrawArcs

Tocreateanarc,youcanspecifyvariouscombinationsofcenter,endpoint,startpoint,radius,angle,chordlength,anddirectionvalues.Curvedobjectsarearcs,circles,polylinearcs,donuts,ellipses,andsplines.1.2.2DrawCircles

Tocreatecircles,youcanspecifyvariouscombinationsofcenter,radius,diameter,pointsonthecircumference,andpointsonotherobjects.1.2.3DrawDonuts

Donutsarefilledringsorsolid-filledcirclesthatactuallyareclosedpolylineswithwidth.1.2.4DrawEllipses

Theshapeofanellipseisdeterminedbytwoaxesthatdefineitslengthandwidth.Thelongeraxisiscalledthemajoraxis,andtheshorteroneistheminoraxis.1.2.5DrawSplines

Asplineisasmoothcurvethatpassesthroughornearagivensetofpoints.Youcancontrolhowcloselythecurvefitsthepoints.第7页1.2.1DrawingArcs

Youcancreatearcsinseveralways.

(1)

DrawArcsbySpecifyingThreePointsStart,Center,End(2)DrawArcsbySpecifyingStart,Center,AngleWhenyouhaveastartpointandacenterpointandtheincludedangle,usetheStart,Center,AngleortheCenter,Start,Angleoption.第8页1.2.1DrawingArcs(3)DrawArcsbySpecifyingStart,Center,LengthWhenyouhaveastartpointandacenterpointyoucansnapto;whenyouknowthechordlength,usetheStart,Center,LengthortheCenter,Start,Lengthoption.Thelengthofthechordofthearcdeterminestheincludedangle.

(4)DrawArcsbySpecifyingStart,End,Direction/Radius第9页1.2.1DrawingArcs(5)DrawContiguousArcsandLines

Immediatelyafteryoucompleteanarc,youcanstartalinetangenttothearcatanendpointbystartingtheLINEcommandandpressingENTERattheSpecifyFirstPointprompt.Youneedtospecifyonlythelinelength.

第10页

1.2.2DrawingCircles

Youcancreatecirclesinseveralways.Thedefaultmethodistospecifythecenterandtheradius.Threeotherwaystodrawacircleareshownintheillustration.第11页1.2.2DrawingCircles

DrawaCircleTangenttoOtherObjects

Tocreateacirclethatistangenttootherobjects,selecttheobjectsandthenspecifytheradiusofthecircle.Intheillustrationsbelow,theboldcircleistheonebeingdrawn,andpoints1and2selecttheobjectstowhichitistangent.第12页1.2.3DrawingDonuts

Donutsarefilledringsorsolid-filledcirclesthatactuallyareclosedpolylineswithwidth.Tocreateadonut,youspecifyitsinsideandoutsidediametersanditscenter.Youcancontinuecreatingmultiplecopieswiththesamediameterbyspecifyingdifferentcenterpoints.Tocreatesolid-filledcircles,specifyaninsidediameterof0.

FillOnFillOff第13页1.2.4DrawingEllipses

Theshapeofanellipseisdeterminedbytwoaxesthatdefineitslengthandwidth.Thelongeraxisiscalledthemajoraxis,andtheshorteroneistheminoraxis.

Theillustrationsbelowshowtwodifferentellipsescreatedbyspecifyingaxisanddistance.Thethirdpointspecifiesonlyadistanceanddoesnotnecessarilydesignatetheaxisendpoint.第14页1.2.4DrawingSplines

Asplineisasmoothcurvethatpassesthroughornearagivensetofpoints.Youcancontrolhowcloselythecurvefitsthepoints.TheSPLINEcommandcreatesaparticulartypeofsplineknownasanonuniformrationalB-spline(NURBS)curve.ANURBScurveproducesasmoothcurvebetweencontrolpoints.Youcreatesplinesbyspecifyingpoints.Youcanclosethesplinesothatthestartandendpointsarecoincidentandtangent.第15页1.2.5DrawingPointsPointobjectsareusefulasnodesorreferencegeometryforobjectsnapsandrelativeoffsets.Youcansetthestyleofthepointsandtheirsizerelativetothescreenorinabsoluteunits.Changingthestyleofpoints

第16页2.ModifyObjects

Ifyouwanttomodifysomeobjects,youmustselecttheminordertobeprocessed.Therearemanywaystoselectobjectsshowninbellow:Whenyouselectsomeobjects,therearemanywaystomodifytheobjectsshowninbellow:

Erase,Copy,Mirror,Offset,Array,Move,Rotate,Scale,Stretch,

Trim,Extend,BreakatPoint,Break,Join,Chamfer,Fillet,Explode第17页3.WorkwithLayers

Layersareliketransparentoverlays.Layersareusedtogroupinformationinadrawingbyfunctionandtoenforcelinetype,color,andotherstandards.Layersaretheprimaryorganizationaltoolusedinrawing.第18页CreatingandNamingLayers

TheLayerPropertiesManagerisdisplayed.Ifyouenter-layerattheCommandprompt,LAYERdisplayspromptsonthecommandline.[?/Mak