Create Polyface Meshes

A polyface mesh represents the surface of an object defined by faces capable of having numerous vertices. Creating a polyface mesh is similar to creating a rectangular mesh. You create a polyface mesh by creating an instance of a PolyFaceMesh object. The constructor of the PolyFaceMesh object does not accept any parameters. To add a vertex to a polyface mesh, you create a PolyFaceMeshVertex and add it to the PolyFaceMesh object using the AppendVertex method.

As you create the polyface mesh, you can set specific edges to be invisible, assign them to layers, or give them colors. To make an edge invisible, you create an instance of a FaceRecord and set which edges should be invisible and then append the FaceRecord object to the PolyFaceMesh object using the AppendFaceRecord method.

Create a polyface mesh

This example creates a PolyfaceMesh object and changes the viewing direction of the active viewport to display the three-dimensional nature of the mesh.

VB.NET

Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

Imports Autodesk.AutoCAD.Geometry

<CommandMethod("CreatePolyfaceMesh")> _

Public Sub CreatePolyfaceMesh()

  '' 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 polyface mesh

      Dim acPFaceMesh As PolyFaceMesh = New PolyFaceMesh()

      '' Add the new object to the block table record and the transaction

      acBlkTblRec.AppendEntity(acPFaceMesh)

      acTrans.AddNewlyCreatedDBObject(acPFaceMesh, True)

      '' Before adding vertexes, the polyline must be in the drawing

      Dim acPts3dPFMesh As Point3dCollection = New Point3dCollection()

      acPts3dPFMesh.Add(New Point3d(4, 7, 0))

      acPts3dPFMesh.Add(New Point3d(5, 7, 0))

      acPts3dPFMesh.Add(New Point3d(6, 7, 0))

      acPts3dPFMesh.Add(New Point3d(4, 6, 0))

      acPts3dPFMesh.Add(New Point3d(5, 6, 0))

      acPts3dPFMesh.Add(New Point3d(6, 6, 1))

      For Each acPt3d As Point3d In acPts3dPFMesh

          Dim acPMeshVer As PolyFaceMeshVertex = New PolyFaceMeshVertex(acPt3d)

          acPFaceMesh.AppendVertex(acPMeshVer)

          acTrans.AddNewlyCreatedDBObject(acPMeshVer, True)

      Next

      Dim acFaceRec1 As FaceRecord = New FaceRecord(1, 2, 5, 4)

      acPFaceMesh.AppendFaceRecord(acFaceRec1)

      acTrans.AddNewlyCreatedDBObject(acFaceRec1, True)

      Dim acFaceRec2 As FaceRecord = New FaceRecord(2, 3, 6, 5)

      acPFaceMesh.AppendFaceRecord(acFaceRec2)

      acTrans.AddNewlyCreatedDBObject(acFaceRec2, True)

      '' 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("CreatePolyfaceMesh")]

public static void CreatePolyfaceMesh()

  // 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 polyface mesh

      PolyFaceMesh acPFaceMesh = new PolyFaceMesh();

      // Add the new object to the block table record and the transaction

      acBlkTblRec.AppendEntity(acPFaceMesh);

      acTrans.AddNewlyCreatedDBObject(acPFaceMesh, true);

      // Before adding vertexes, the polyline must be in the drawing

      Point3dCollection acPts3dPFMesh = new Point3dCollection();

      acPts3dPFMesh.Add(new Point3d(4, 7, 0));

      acPts3dPFMesh.Add(new Point3d(5, 7, 0));

      acPts3dPFMesh.Add(new Point3d(6, 7, 0));

      acPts3dPFMesh.Add(new Point3d(4, 6, 0));

      acPts3dPFMesh.Add(new Point3d(5, 6, 0));

      acPts3dPFMesh.Add(new Point3d(6, 6, 1));

      foreach (Point3d acPt3d in acPts3dPFMesh)

          PolyFaceMeshVertex acPMeshVer = new PolyFaceMeshVertex(acPt3d);

          acPFaceMesh.AppendVertex(acPMeshVer);

          acTrans.AddNewlyCreatedDBObject(acPMeshVer, true);

      FaceRecord acFaceRec1 = new FaceRecord(1, 2, 5, 4);

      acPFaceMesh.AppendFaceRecord(acFaceRec1);

      acTrans.AddNewlyCreatedDBObject(acFaceRec1, true);

      FaceRecord acFaceRec2 = new FaceRecord(2, 3, 6, 5);

      acPFaceMesh.AppendFaceRecord(acFaceRec2);

      acTrans.AddNewlyCreatedDBObject(acFaceRec2, 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();

VBA/ActiveX Code Reference