第3章平面立体的投影ppt课件

.,SummaryofPolyhedralSolids平面立体概述Prism棱柱Pyramid棱锥Exercise练习题,ProjectionofPolyhedralSolids平面立体的投影,请点击相应标题显示其内容,.,SummaryofPolyhedralSolids平面立体概述,Prisms棱柱,Intersectionlinesofedgeplanesarecallededgelines.Intersectionlinesofedgeplanesandbasesarecalledbaseedgelines.Whendrawingprojectionsofpolyhedralsolids,weareactuallydrawingtheprojectionsofalledgelinesandbaseedgelinesfollowedbyavisibilitytestoftheprojectededgelinesandbaseedgelines.各棱面的交线称为棱线,棱面与底面的交线称为底边,画平面立体的投影图,实质是画出所有棱线和底边的投影,并判别其可见性。,Pyramids棱锥,Polyhedralsolids平面立体,请点击鼠标左键显示后面内容,Polyhedralsolids:Thesolidsthataresurroundedbyplanesarecalledpolyhedralsolids.平面立体:完全由平面围成的立体称为平面立体。,.,Classbythebasesofprisms根据棱柱底面形状可分为:,Triangularprism三棱柱,Prism棱柱,Squareprism四棱柱,Pentagonalprism五棱柱,Hexagonalprism六棱柱,Drawsteps画图步骤：,Drawcenterlinesanddatumlines.先画中心线和基准线;Addlinesfortheupperandlower(end)faces.再画反映顶部或底部(端面)形状的视图;Completethreeviews.按三等规律画全三视图。,请点击鼠标左键显示后面内容,五棱柱的投影演示,1.Projectionofaprism棱柱的投影,.,Example3.Drawthepentagonalprismandgetpointsonthesurface.画五棱柱及表面上各点的三视图。,Theprojectionofpointisnotvisiblewhenitisoninvisibleedgeorplane.凡在不可见表面及棱线上的点,其投影则为不可见。,Identification判别:,Theprojectionofpointisalsovisiblewhenitisonvisibleedgeorplane.凡在可见表面及棱线上的点,其投影为可见;,Method方法:,Gettingpointsonsurfacesofaprismcanbebasedontheaccumulationcharacteristicsofedgelinesorplaneprojection.棱柱表面上的点可利用棱线或棱面的积聚性投影求之。,2.Gettingpointsonthesurfaceofaprism棱柱表面上取点,Labeling标注:,Allinvisiblepointsarewritteninbrackets.对不可见的点加括号以示区别。,请点击鼠标左键显示后面内容,Example1.Drawthetriangularprismandgetpointsonthesurface.画三棱柱及表面上各点的三视图。,Example2.Drawthesquareprismandgetpointsonthesurface.画四棱柱及表面上各点的三视图。,Prism棱柱,.,Classbythebasesofapyramid根据棱锥底面形状可分为:,Triangularpyramid三棱锥,1.Projectionofpyramid棱锥的投影,Squarepyramid四棱锥,Pentagonalpyramid五棱锥,Hexagonalpyramid六棱锥,Drawsteps画图步骤：,1.Drawsymmetrylinesandthebaseofthepyramid.先画锥底面形状的投影;2.Addthevertexofthepyramid.再画锥顶点的投影;3.Completethreeviewsafteraddinglinesforthesidefaces.最后画各棱线的投影。,请点击鼠标左键显示后面内容,Pyramid棱锥,.,2.Gettingpointsonthesurfaceofapyramid棱锥表面取点,Drawanauxiliarylineorplanegoingthroughthepointonthepyramid.在棱面上过锥顶作一条包含该点的辅助线或辅助平面。,Distinguish判别:,Labeling标注:,Allinvisiblepointsarewritteninbrackets.对不可见的点加括号以示区别。,请点击鼠标左键显示后面内容,Example4.Drawaregulartriangularpyramidandgetpointsonthesurface.画正三棱锥及表面上各点的三视图。,Example5.Drawaregularpentagonalpyramidandgetpointsonthesurface.画正五棱锥及表面上各点的三视图。,Pyramid棱锥,Theprojectionofpointisalsovisiblewhenitonvisibleedgeorplane.凡在可见表面及棱线上的点,其投影为可见；,Theprojectionofpointisnotvisiblewhenitoninvisibleedgeorplane.凡在不可见表面及棱线上的点,其投影则为不可见。,Method方法:,.,a,Exercise.Completeeachdrawingbyaddingthemissingdetail.补全平面立体及其表面上各点的三投影。,（1）Drawaprismandgetpointsonthesurface.画三棱柱及各点的三投影。,a,b,c,请点击解答显示其内容,(c),(b),.,本小节结束,谢谢您的认真学习！,退出,前一页,.,Example1.Drawthetriangularprismandgetpointsonthesurface.画三棱柱及表面上各点的三视图。,Drawviewoftheendfaces.先画反映端面形状的视图;Completethreeviews.再按三等规律画全三视图;Drawallviewsofpoints.求各点的三投影。,请点击鼠标左键显示后面内容,Steps作图步骤：,a,a,(b),b,.,d,Example2.Drawthesquareprismandgetpointsonthesurface.画四棱柱及表面上各点的三视图。,请点击鼠标左键显示后面内容,Drawviewoftheendfaces.先画反映端面形状的视图;Completethreeviews.再按三等规律画全三视图;Drawallviewsofpoints.求各点的三投影。,Steps作图步骤：,c,d,（c),.,Example3.Drawthepentagonalprismandgetpointsonthesurface.画五棱柱及表面上各点的三视图。,Steps作图步骤：,（1）Drawtheaccumulationtopview.先画有积聚性的俯视图;,（2）Drawthelimitelements.再画主视图各棱线的投影;,（3）Drawallviewsofprism.根据投影规律求第三投影;,（4）Drawallviewsofpoints.求各点的三投影。,请点击鼠标左键显示后面内容,e,e,（f),f,f,e,.,abc,Steps作图步骤：,Example4.Drawaregulartriangularpyramidandgetpointsonthesurface.画正三棱锥及表面上各点的三视图。,（1）Drawthetopview.先画俯视图;,（2）Drawthelimitelements.再画主视图各棱线的投影;,（3）Drawallviewsofpyramid.根据投影规律求第三投影;,（4）DrawallviewsofpointD.用辅助素线法求D点的三投影;,（5）DrawallviewsofpointE.用辅助平面法求E点的三投影。,请点击鼠标左键显示后面内容,a(c)b,d,（d),e,e,e,d,k,k,p,.,Example5.Drawaregularpentagonalpyramidandgetpointsonthesurface.画正五棱锥及表面上各点的三视图。,Steps作图步骤：,1）Drawthetopview.先画俯视图;,2）Drawthelimitelements.再画主视图各棱线的投影。,3）Drawallviewsofpyramid.根据投影规律求第三投影;,4）Drawa