AutoCAD .Net 创建线性标注

以下代码展示：
在模型空间中创建如下图所示的线性尺寸。

线性标注尺寸对象是RotatedDimension。
当RotatedDimension.Rotation 为 0 时，创建的是水平标注。
当RotatedDimension.Rotation 为 Math.PI / 2 时，创建的是竖直标注。

using Autodesk.AutoCAD.Runtime;using Autodesk.AutoCAD.ApplicationServices;using Autodesk.AutoCAD.DatabaseServices;using Autodesk.AutoCAD.Geometry;using Autodesk.AutoCAD.EditorInput;using Autodesk.AutoCAD.Colors;[CommandMethod("NewLinearDim")]public static void NewLinearDim(){    Document doc = Application.DocumentManager.MdiActiveDocument;    Database db = doc.Database;    using (Transaction tr = db.TransactionManager.StartTransaction())    {        //-------------------------------        // 获取模型空间        //-------------------------------        BlockTable blockTbl = tr.GetObject(            db.BlockTableId, OpenMode.ForRead) as BlockTable;        BlockTableRecord modelSpace = tr.GetObject(            blockTbl[BlockTableRecord.ModelSpace], OpenMode.ForWrite) as BlockTableRecord;        //-------------------------------        // 创建水平标注        //-------------------------------        RotatedDimension hdim = new RotatedDimension();        hdim.XLine1Point = new Point3d(10, 15, 0);        hdim.XLine2Point = new Point3d(20, 20, 0);        hdim.Rotation = 0;        hdim.DimLinePoint = new Point3d(0, 25, 0);        hdim.DimensionStyle = db.Dimstyle;        //-------------------------------        // 创建竖直标注        //-------------------------------        RotatedDimension vdim = new RotatedDimension();        vdim.XLine1Point = new Point3d(10, 15, 0);        vdim.XLine2Point = new Point3d(20, 20, 0);        vdim.Rotation = Math.PI / 2;        vdim.DimLinePoint = new Point3d(25, 0, 0);        vdim.DimensionStyle = db.Dimstyle;        //-------------------------------        // 添加到模型空间并提交到数据库        //-------------------------------        modelSpace.AppendEntity(hdim);        tr.AddNewlyCreatedDBObject(hdim, true);        modelSpace.AppendEntity(vdim);        tr.AddNewlyCreatedDBObject(vdim, true);        tr.Commit();    }}

XLine1Point、XLine2Point 指定尺寸界线的位置。
DimLinePoint 用于确定尺寸线的位置。

AutoCAD 尺寸对象的具体组成如下:

* 尺寸线 Dimension Line
* 尺寸文本 Dimension Text
* 尺寸界线 Extention Line
* 箭头 Arrowhead