(点的投影)习题与解答.ppt

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1、点的投影习题与解答Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.空间内V面上OX轴上H面上步骤与答案Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.步骤与答案bacc″a′a″b′b″c′Evaluati

2、ononly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.aa″b′bb″cc′(a′)c″d′dd″12251010151015151220步骤与答案Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.步骤与答案a′a25Evalua

3、tiononly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.b′bc″c′(　　）d′a(d)d″步骤与答案Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.步骤与答案YWa″XYHZOEvaluationonly.Createdw

4、ithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.3.3直线的投影Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.ABPCDPPEF一、直线在单一投影面上的投影a（b）直线垂直于投影面：直线在该投影面上的投影积聚为点cdef直线平行于投影面：直线在该投

5、影面上的投影反映实长直线倾斜于投影面：直线在该投影面上的投影缩短Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.二、直线在三投影面体系中的投影相对于投影面名称HVW规定夹角的名称直线与投影面夹角的规定名称Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyr

6、ight2004-2011AsposePtyLtd.1．投影面垂直线的投影ABPa（b）在三投影面体系中，当直线垂直于某一个投影面时，则必同时平行于另两个投影面，这样的直线称为投影面垂直线。共有三种投影面垂直线：直线⊥投影面V：正垂线直线⊥投影面H：铅垂线直线⊥投影面W：侧垂线Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.以正垂线AB为例，讨论其投影特性：

7、WVHABa‘（b’）abb”a”a’（b’）aba”b”∵AB⊥V，∴AB∥H，AB∥W。①a’、b’重影②ab=a”b”=AB=LAB③ab⊥OX,a”b”⊥OZ④=90°、==0°投影特性：投影面垂直线在所垂直的投影面上的投影积聚为一点；另外两个投影反映实长，且垂直于相应的轴。XOYWZYHEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.2．投影

8、面平行线的投影在三投影面体系中，当直线平行于某一个投影面，同时与另两个投影面倾斜，这样的直线称为投影面平行线。CDPcd共有三种投影面平行线：直线∥投影面V：正平线直线∥投影面H：水平线直线∥投影面W：侧平线Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePty