《01国家标准,尺寸标注,图形绘制方法.ppt

画连接弧时，需要用到平面几何中以下两条原理。 (1) 与已知直线相切且半径为R的圆弧，其圆心轨迹为与已知直线平行且距离为R的两直线，连接点为圆心向已知直线所作垂线的垂足。 (2) 与已知圆弧相切的圆弧，其圆心轨迹为已知圆弧的同心圆，其半径为：外切时，连接圆弧与已知圆弧的半径之和；内切时，连接圆弧与已知圆弧的半径之差。连接点为：外切时，连心线与已知圆弧的交点；内切时，连心线的延长线与已知圆弧的交点。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 例1.1 用半径为R的圆弧连接两直线AB和BC，如图所示。 作图步骤： (1) 求圆心：分别作与已知直线AB、BC相距为R的平行线，其交点为Ｏ，即为连接弧（半径R）的圆心； (2) 求切点：自点O分别向直线AB及BC作垂线，得垂足K1和K2，即为切点； (3) 画连接弧：以O为圆心，R为半径，自点K1至K2画圆弧，即完成作图。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 例1.2 用半径为R的圆弧连接两已知圆弧（R1、R2），如图所示。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. (1) 求圆心：分别以O1、O2为圆心，R1＋R和R2＋R（外切时，如图（a）所示）、或R－R1和R－R2（内切时，如图（b）所示）、或R1－R和R2＋R（内、外切，如图（c）所示）为半径画弧，得交点O，即为连接弧（半径R）的圆心； (2) 求切点：作两圆心连线O1O、O2O或O1O、O2O的延长线，与两已知圆弧（半径R1、R2）相交于点K1、K2，则K1、K2即为切点； (3) 画连接弧：以O为圆心，R为半径，自点K1至K2画圆弧，即完成作图。 作图步骤： Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 画平面图形前，首先要对平面图形进行尺寸分析和线段性质分析，然后才能正确画出 平面图形和进行平面图形的尺寸标注。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-20