实验二 AutoCAD基本图形对象创建与编辑
一、主要内容
1. 创建直线 2. 创建圆 3. 创建圆弧 4. 创建多段线 5. 创建椭圆 6. 样条曲线 7. 创建面域 8. 创建文字 9. 创建填充 10. 创建尺寸标注 11. 创建三维实体
二、学时安排：2学时 三、预习内容
回顾AutoCAD图形对象创建的一般过程。四、基本图形对象创建与编辑
基本图形对象创建:添加引用
using System;
using System.Collections.Generic; using System.Linq; using System.Text;
using System.Threading.Tasks; using Autodesk.AutoCAD.Runtime; using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.DatabaseServices; using Autodesk.AutoCAD.ApplicationServices; using Autodesk.AutoCAD.EditorInput; using System.Windows;
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4.1 创建直线对象
① 创建直线并返回新建直线对象标识
代码：[CommandMethod(\)]
public void CreateLine() {
using (Transaction trans = db.TransactionManager.StartTransaction()) {
//创建直线
Point3d pt1 = new Point3d(20, 20, 0); Point3d pt2 = new Point3d(100, 100, 0); Line lineEnt = new Line(pt1, pt2); lineEnt.ColorIndex = 1; //获得块表
BlockTable bt = (BlockTable)trans.GetObject( db.BlockTableId, OpenMode.ForRead); //获得特定块表记录
BlockTableRecord btr = (BlockTableRecord)trans.GetObject( bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite); //把图形对象的记录加入到块表记录
pModifyEntID = btr.AppendEntity(lineEnt); //将直线添加到事务处理中
trans.AddNewlyCreatedDBObject(lineEnt, true); trans.Commit(); }
}
② 比较Autodesk.AutoCAD.DatabaseServices.Line、
Autodesk.AutoCAD.Geometry.Line2d和Autodesk.AutoCAD.Geometry.Line3d
③ 修改新建直线对象
代码：
[CommandMethod(\)] public void ModifyLine() {
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Database db = HostApplicationServices.WorkingDatabase;
using (Transaction trans = db.TransactionManager.StartTransaction()) {
BlockTable bt = (BlockTable)trans.GetObject( db.BlockTableId, OpenMode.ForRead);
BlockTableRecord btr = (BlockTableRecord)trans.GetObject( bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite); foreach (ObjectId pEntId in btr) {
//打开要修改的图形对象
Entity pEnt = (Entity)trans.GetObject(pEntId, OpenMode.ForWrite); if (pEnt.Layer == \房屋\) //修改颜色
pEnt.ColorIndex = 1; pEnt.Close(); }
trans.Commit(); }
}
4.2 创建圆
使用Autodesk.AutoCAD.DatabaseServices.Circle类创建圆
代码：
[CommandMethod(\)] public void Circle() {
Circle c = new Circle();
c.Center = new Point3d(0, 0, 0); c.Radius = 100;
Database db = HostApplicationServices.WorkingDatabase;
using (Transaction trans = db.TransactionManager.StartTransaction()) {
//创建块表
BlockTable c_block = (BlockTable)trans.GetObject( db.BlockTableId, OpenMode.ForRead);//读取，0
BlockTableRecord c_block_record = (BlockTableRecord)trans.GetObject( c_block[BlockTableRecord.ModelSpace], OpenMode.ForWrite);
c_block_record.AppendEntity(c);//块表记录追加实体，把图形对象的记录加入到块表记录 trans.AddNewlyCreatedDBObject(c, true);//将圆添加到事务处理中 trans.Commit();//提交事务 }
}
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4.3 创建圆弧
→使用Autodesk.AutoCAD.DatabaseServices.Arc类创建一圆弧
代码：
[CommandMethod(\)]//创建圆弧 public void CreatArc() {
Database db = HostApplicationServices.WorkingDatabase;
using (Transaction trans = db.TransactionManager.StartTransaction()) {
Arc pArc = new Arc(new Point3d(50, 50, 0), 100, 0, 100); BlockTable bt = (BlockTable)trans.GetObject( db.BlockTableId, OpenMode.ForRead);
BlockTableRecord btr = (BlockTableRecord)trans.GetObject( bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite); btr.AppendEntity(pArc);
trans.AddNewlyCreatedDBObject(pArc, true); trans.Commit(); }
}
→给定圆弧外一点，计算该点到圆弧的切线，具体操作如下： ①将圆弧转成Autodesk.AutoCAD.Geometry.CircularArc2d
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②使用CircularArc2d 的GetTangent(Autodesk.AutoCAD.Geometry.Point2d point)方法计算切线，该方法返回结果为Autodesk.AutoCAD.Geometry.Line2d类的实例对象
③将Line2d实例对象转换成Autodesk.AutoCAD.DatabaseServices.Line 4.4 创建多段线 1）创建Polyline
①创建一条具有5个顶点的、且带有2-3个凸度的多段线 ②遍历多段线的所有片段Segment，并判断每个片段类型
③将Polyline转换成Polyline2d并分别执行CurveFit和SplineFit操作 2）创建Polyline2d
①分别创建CubicSplinePoly（三次拟合）、QuadSplinePoly（四次拟合）、FitCurvePoly（曲线拟合）和SimplePoly（无拟合）四种类型的Polyline2d，顶点个数为5，并比较它们之间的差异
②分别遍历四种类型Polyline2d的所有片段，并判断每个片段类型，能读取所有片段吗？为什么？
③把Polyline2d转换成Polyline，行吗？ 3）创建Polyline3d
代码：
[CommandMethod(\)]//创建多段线 public void createPloyline1() {
Polyline pl = new Polyline(5);
Database db = HostApplicationServices.WorkingDatabase;
using (Transaction trans = db.TransactionManager.StartTransaction()) {
Point2d p1 = new Point2d(50, 10); Point2d p2 = new Point2d(100, 30); Point2d p3 = new Point2d(150, 60); Point2d p4 = new Point2d(200, 90); Point2d p5 = new Point2d(250, 120);
Point2dCollection pc = new Point2dCollection(); pc.Add(p1); pc.Add(p2); pc.Add(p3); pc.Add(p4); pc.Add(p5);
for (int i = 0; i < 5; i++) {
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