创建实体 （.NET）

实体对象（Solid3d 对象）表示对象的整个体积。实体是 3D 建模类型中信息最完整、最不模糊的。复杂的实体形状也比线框和网格更容易构建和编辑。

您可以使用对象的成员方法和属性创建基本的实体形状，例如盒子、球体和楔形等。还可以沿路径拉伸区域对象或绕轴旋转 2D 对象。Solid3d

与网格一样，实体显示为线框，直到您隐藏、着色或渲染它们。此外，您还可以分析固体的质量属性（体积、惯性矩、重心等）。使用以下属性，可以查询与该对象关联的对象。该对象包含以下属性，可用于分析实体：、、和MassPropertiesSolid3dMassPropertiesSolid3dSolid3dMassPropertiesMomentOfInertiaPrincipalAxesPrincipalMomentsProductOfInertiaRadiiOfGyrationVolume.

实体的显示受当前视觉样式和与 3D 建模相关的系统变量的影响。影响实体显示的一些系统变量是 ISOLINES 和 FACETRES。ISOLINES 控制用于可视化线框曲线部分的曲面细分线的数量，而 FACETRES 则调整着色和隐藏线对象的平滑度。

创建楔形实体

下面的示例创建一个楔形实体。活动视口的查看方向将更新，以显示楔块的三维性质。

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
 
<CommandMethod("CreateWedge")> _
Public Sub CreateWedge()
    '' Get the current document and database, and start a transaction
    Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument
    Dim acCurDb As Database = acDoc.Database

    Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()
        '' Open the Block table for read
        Dim acBlkTbl As BlockTable
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, _
                                     OpenMode.ForRead)

        '' Open the Block table record Model space for write
        Dim acBlkTblRec As BlockTableRecord
        acBlkTblRec = acTrans.GetObject(acBlkTbl(BlockTableRecord.ModelSpace), _
                                        OpenMode.ForWrite)

        '' Create a 3D solid wedge
        Using acSol3D As Solid3d = New Solid3d()
            acSol3D.CreateWedge(10, 15, 20)

            '' Position the center of the 3D solid at (5,5,0) 
            acSol3D.TransformBy(Matrix3d.Displacement(New Point3d(5, 5, 0) - _
                                                      Point3d.Origin))

            '' Add the new object to the block table record and the transaction
            acBlkTblRec.AppendEntity(acSol3D)
            acTrans.AddNewlyCreatedDBObject(acSol3D, True)
        End Using

        '' Open the active viewport
        Dim acVportTblRec As ViewportTableRecord
        acVportTblRec = acTrans.GetObject(acDoc.Editor.ActiveViewportId, _
                                          OpenMode.ForWrite)

        '' Rotate the view direction of the current viewport
        acVportTblRec.ViewDirection = New Vector3d(-1, -1, 1)
        acDoc.Editor.UpdateTiledViewportsFromDatabase()

        '' Save the new objects to the database
        acTrans.Commit()
    End Using
End Sub

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
 
[CommandMethod("CreateWedge")]
public static void CreateWedge()
{
    // Get the current document and database, and start a transaction
    Document acDoc = Application.DocumentManager.MdiActiveDocument;
    Database acCurDb = acDoc.Database;

    using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
    {
        // Open the Block table record for read
        BlockTable acBlkTbl;
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId,
                                        OpenMode.ForRead) as BlockTable;

        // Open the Block table record Model space for write
        BlockTableRecord acBlkTblRec;
        acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],
                                        OpenMode.ForWrite) as BlockTableRecord;

        // Create a 3D solid wedge
        using (Solid3d acSol3D = new Solid3d())
        {
            acSol3D.CreateWedge(10, 15, 20);

            // Position the center of the 3D solid at (5,5,0) 
            acSol3D.TransformBy(Matrix3d.Displacement(new Point3d(5, 5, 0) -
                                                        Point3d.Origin));

            // Add the new object to the block table record and the transaction
            acBlkTblRec.AppendEntity(acSol3D);
            acTrans.AddNewlyCreatedDBObject(acSol3D, true);
        }

        // Open the active viewport
        ViewportTableRecord acVportTblRec;
        acVportTblRec = acTrans.GetObject(acDoc.Editor.ActiveViewportId,
                                            OpenMode.ForWrite) as ViewportTableRecord;

        // Rotate the view direction of the current viewport
        acVportTblRec.ViewDirection = new Vector3d(-1, -1, 1);
        acDoc.Editor.UpdateTiledViewportsFromDatabase();

        // Save the new objects to the database
        acTrans.Commit();
    }
}

Sub CreateWedge()
    Dim wedgeObj As Acad3DSolid
    Dim center(0 To 2) As Double
    Dim length As Double
    Dim width As Double
    Dim height As Double
 
    ' Define the wedge
    center(0) = 5#: center(1) = 5#: center(2) = 0
    length = 10#: width = 15#: height = 20#
 
    ' Create the wedge in model space
    Set wedgeObj = ThisDrawing.ModelSpace. _
                       AddWedge(center, length, width, height)
 
    ' Change the viewing direction of the viewport
    Dim NewDirection(0 To 2) As Double
    NewDirection(0) = -1
    NewDirection(1) = -1
    NewDirection(2) = 1
    ThisDrawing.ActiveViewport.direction = NewDirection
    ThisDrawing.ActiveViewport = ThisDrawing.ActiveViewport
 
    ZoomAll
End Sub