消除AutoCAD网格中的对角线（C#）

我正在尝试在AutoCAD中绘制一个由一系列矩形组成的墙。我想使用网格将它们渲染为实体对象。我得到了它，所以视觉效果看起来很像我想要的，除了在每个矩形中有看似随机的对角线

我想要的只是一个简单的矩形。下面是我绘制矩形网格的代码

public static ObjectId DrawPolyhedronMesh(Polyhedron polyhedronToDraw, string layerToInsertOn = "0")
{
    using (Transaction acTrans = _database.TransactionManager.StartTransaction())
    {
        // Open the Block table record for read
        BlockTable acBlkTbl = acTrans.GetObject(_database.BlockTableId, OpenMode.ForRead) as BlockTable;

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

        // Create a polygon mesh
        PolygonMesh acPolyMesh = new PolygonMesh();
        acPolyMesh.Layer = layerToInsertOn;
        acPolyMesh.MSize = 12;
        acPolyMesh.NSize = 2;
        acPolyMesh.MakeMOpen();
        acPolyMesh.MakeNOpen();

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

        // Before adding vertices, the polyline must be in the drawing
        Point3dCollection acPts3dPMesh = new Point3dCollection();
        foreach (PlaneRegion f in polyhedronToDraw.Faces)
        {
            foreach (Point p in f.Vertices)
            {
                acPts3dPMesh.Add(GeometryAdapter.ClearspanPointToAcadPoint(p));
            }
        }

        foreach (Point3d acPt3d in acPts3dPMesh)
        {
            PolygonMeshVertex acPMeshVer = new PolygonMeshVertex(acPt3d);
            acPolyMesh.AppendVertex(acPMeshVer);
            acTrans.AddNewlyCreatedDBObject(acPMeshVer, true);
        }

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

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

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

基本上，为了绘制网格，我遍历矩形的每个面，并将形成该面的每个顶点添加到网格中。我怎样才能改变这种方法，去掉对角线，只剩下基本的矩形呢