第九章三维实体造型

AutoCAD2000应用基础教程第九章三维实体造型-50-第九章三维实体造型§9-1三维实体造型的基本概念9.1.1线框模型线框模型是三维对象的轮廓描述，它是由描述三维对象边框的点、直线、曲线组成。利用AutoCAD，用户可以在三维空间中用二维绘图的方法建立线框模型。线框模型不能进行消影、渲染等操作。9.1.2表面模型表面模型不仅定义了三维对象的边界，而且还定义了它的表面，因此表面模型具有面的特征。AutoCAD的表面模型是用多边形网格（MESH）表示的。9.1.3实体模型实体模型具有体的特征，用户可以对它进行布尔运算和三维编辑。实体模型可以用线框模型或表面模型的显示方式显示。9.1.4面域面域是指其内部可以含有孔、岛的具有边界的平面。AutoCAD可以把一些对象围成的封闭区域建立成面域。9.1.5用户坐标系USC命令：USC工具条：如图9-1所示。菜单：工具/新建UCS，如图9-2所示。9.1.6实体编辑(布尔运算)工具条：如图9-3所示。菜单：修改/实体编辑，如图9-4所示。图9-1USC工具条图9-2USC菜单图9-3实体编辑工具条AutoCAD2000应用基础教程第九章三维实体造型-51-9.2实例绘制连接板的实体造型，如图9-5所示。操作步骤：9.2.1设置图形界限和单位Command:limits：0,01188,840Command:ddunits：单位=小数精度=0角度=度精度=0Command:zZOOMAll/Center/Dynamic/Extents/Previous/Scale(X/XP)/Window/Realtime:a9.2.2创建旋转体⑴Command:lineFrompoint:Topoint:@0,60Topoint:@50,0Topoint:@0,-100Topoint:@-90,0Topoint:回车图9-5连接板的实体造型图9-4实体编辑菜单图9-6AutoCAD2000应用基础教程第九章三维实体造型-52-完成后的图形如图9-6所示。⑵Command:circle3P/2P/TTR/Centerpoint:tEnterTangentspec:EntersecondTangentspec:Radius:40完成后的图形如图9-7所示。⑶Command:trimSelectcuttingedges:(Projmode=UCS,Edgemode=Noextend)Selectobjects:1found(选择直线1，如图5-7)Selectobjects:1found(选择直线2，如图5-7)Selectobjects:回车Selectobjecttotrim/Project/Edge/Undo:回车(选择圆弧3，如图9-7)完成后的图形如图9-8所示。⑷Command:regionSelectobjects:Othercorner:5found(选择所有元素)Selectobjects:回车1loopextracted.1Regioncreated.⑸Command:revolveSelectobjects:1found(选择面域对象)Selectobjects:回车Axisofrevolution-Object/X/Y/Startpointofaxis:Pointoroptionkeywordrequired.Axisofrevolution-Object/X/Y/Startpointofaxis:'_osnap(选择45直线的4点，如图9-8)ResumingREVOLVEcommand.Axisofrevolution-Object/X/Y/Startpointofaxis:图9-7图9-8图9-9123AutoCAD2000应用基础教程第九章三维实体造型-53-Endpointofaxis:(选择45直线的5点，如图9-8)Angleofrevolutionfullcircle:回车完成后的图形如图9-9所示。⑹Command:vpointRotate/Viewpoint0.0000,0.0000,1.0000:1,-1,1Regeneratingdrawing.完成后的图形如图9-10所示。9.2.3创建平板⑴Command:ucsOrigin/ZAxis/3point/OBject/View/X/Y/Z/Prev/Restore/Save/Del/?/World:3Originpoint0,0,0:_cenof(选取大圆的圆心)PointonpositiveportionoftheX-axis275.3823,137.7632,0.0000:_quaof(选取大圆的四分点)Pointonpositive-YportionoftheUCSXYplane274.3823,138.7632,0.0000:_quaof(选取大圆的四分点)⑵Command:planCurrentUCS/Ucs/World:回车Regeneratingdrawing.完成后的图形如图9-11所示。⑶Command:'_zoom（将对象缩小）All/Center/Dynamic/Extents/Previous/Scale(X/XP)/Window/Realtime:PressEscorEntertoexit,orright-clicktoactivatepop-upmenu.⑷Command:'_panPressEscorEntertoexit,orright-clicktoactivatepop-upmenu.⑸Command:circle3P/2P/TTR/Centerpoint:Pointoroptionkeywordrequired.3P/2P/TTR/Centerpoint:_cenofDiameter/Radius:150Command:_lineFrompoint:_quaof(选取大圆的四分点)Topoint:@0,-500图9-10图9-11图9-12AutoCAD2000应用基础教程第九章三维实体造型-54-Topoint:回车Command:LineFrompoint:_quaof(选取大圆的四分点)Topoint:@0,-500Topoint:回车完成后的图形如图9-12所示。⑹Command:trimSelectcuttingedges:(Projmode=UCS,Edgemode=Noextend)Selectobjects:1found(选择直线6，如图9-12)Selectobjects:1found(选择直线7，如图9-12)Selectobjects:回车Selectobjecttotrim/Project/Edge/Undo:(选择圆弧8，如图9-12)Selectobjecttotrim/Project/Edge/Undo:回车Command:_vpoint***SwitchingtotheWCS***Rotate/Viewpoint0.0000,-1.0000,0.0000:_non*1,-1,1***ReturningtotheUCS***Regeneratingdrawing.完成后的图形如图9-13所示。Command:_regionSelectobjects:all14found9wereonalockedlayer.Selectobjects:回车1closed,degenerateorunsupportedobjectrejected.1loopextracted.1Regioncreated.Command:_extrudeSelectobjects:1found(选择面域)Selectobjects:回车Path/HeightofExtrusion:30Extrusiontaperangle0:图9-13图9-14AutoCAD2000应用基础教程第九章三维实体造型-55-完成后的图形如图9-14所示。9.2.4创建斜板Command:planCurrentUCS/Ucs/World:Regeneratingdrawing.Command:'_zoom(“实时缩放”工具钮)All/Center/Dynamic/Extents/Previous/Scale(X/XP)/Window/Realtime:PressEscorEntertoexit,orright-clicktoactivatepop-upmenu.Command:'_pan(“实时平移”工具钮)PressEscorEntertoexit,orright-clicktoactivatepop-upmenu.完成后的图形如图9-15所示。Command:_rectangChamfer/Elevation/Fillet/Thickness/Width/Firstcorner:(选取左下角的1点，如图9-15)Othercorner:@300,-200完成后的图形如图9-16所示。Command:_vpoint(“东南视图”工具钮)***SwitchingtotheWCS***Rotate/Viewpoint0.0000,-1.0000,0.0000:_non*1,-1,1***ReturningtotheUCS***Regeneratingdrawing.Command:_extrude(“拉伸”工具钮)Selectobjects:1found(选择矩形)Selectobjects:回车Path/HeightofExtrusion:30Extrusiontaperangle0:完成后的图形如图9-17所示。Command:_circle3P/2P/TTR/Centerpoint:_trackingFirsttrackingpoint:（“圆”工具钮）（点击“Ctrl+右键”后，在弹出菜单中选择“追综”）Nextpoint(PressENTERtoendtracking):80Nextpoint(PressENTERtoendtracking):80图9-15图9-16图9-171AutoCAD2000应用基础教程第九章三维实体造型-56-Nextpoint(PressENTERtoendtracking):回车Diameter/Radius:30Command:copySelectobjects:1found(选择圆)Selectobjects:回车Basepointordisplacement/Multiple:_cenofSecondpointofdisplacement:140(选取圆心作为基点，并利用“在指定方向上通过给定距离确定点”的方法给定位移)Command:_extrude(“拉伸”工具钮)(拉伸左边圆柱)Selectobjects:1foundSelectobjects:回车Path/HeightofExtrusion:30Extrusiontaperangle0:回车Command:_extrude(“拉伸”工具钮)(拉伸右边圆柱)Selectobjects:1foundSelectobjects:回车Path/HeightofExtrusion:30Extrusiontaperangle0:回车完成后的图形如图9-18所示。Command:_subtractSelectsolidsandregionstosubtractfrom...(菜单“修改\布尔运算\相减”)Selectobjects:1found(选择下面的长方体)Selectobjects:回车Selectsolidsandregionstosubtract...Selectobjects:1found(选择左面的圆体柱)Selectobjects:回车Command:_subtractSelectsolidsandregionsto