Define the Hatch Boundaries

Once the Hatch object is created, the hatch boundaries can be added. Boundaries can be any combination of lines, arcs, circles, 2D polylines, ellipses, splines, and regions.

The first boundary added must be the outer boundary, which defines the outermost limits to be filled by the hatch. To add the outer boundary, use the AppendLoop method with the HatchLoopTypes.Outermost constant for the type of loop to append.

Once the outer boundary is defined, you can continue adding additional boundaries. Add inner boundaries using the AppendLoop method with the HatchLoopTypes.Default constant.

Inner boundaries define islands within the hatch. How these islands are handled by the Hatch object depends on the setting of the HatchStyle property. The HatchStyle property can be set to one of the following conditions:

Hatch style definitions
HatchStyle	Condition	Description
	Normal (HatchStyle.Normal)	Specifies standard style, or normal. This option hatches inward from the outermost area boundary. If AutoCAD encounters an internal boundary, it turns off hatching until it encounters another boundary. This is the default setting for the HatchStyle property.
	Outer (HatchStyle.Outer)	Fills the outermost areas only. This style also hatches inward from the area boundary, but it turns off hatching if it encounters an internal boundary and does not turn it back on again.
	Ignore (HatchStyle.Ignore)	Ignores internal structure. This option hatches through all internal objects.

When you have finished defining the hatch it must be evaluated before it can be displayed. Use the EvaluateHatch method to do this.

Create a Hatch object

The following example creates an associated hatch in Model space. Once the hatch has been created, you can change the size of the circle that the hatch is associated with. The hatch will change to match the size of the circle.

VB.NET

Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

Imports Autodesk.AutoCAD.Geometry

<CommandMethod("AddHatch")> _

Public Sub AddHatch()

  '' Get the current document and database

  Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument

  Dim acCurDb As Database = acDoc.Database

  '' Start a transaction

  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 circle object for the closed boundary to hatch

      Dim acCirc As Circle = New Circle()

      acCirc.Center = New Point3d(3, 3, 0)

      acCirc.Radius = 1

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

      acBlkTblRec.AppendEntity(acCirc)

      acTrans.AddNewlyCreatedDBObject(acCirc, True)

      '' Adds the circle to an object id array

      Dim acObjIdColl As ObjectIdCollection = New ObjectIdCollection()

      acObjIdColl.Add(acCirc.ObjectId)

      '' Create the hatch object and append it to the block table record

      Dim acHatch As Hatch = New Hatch()

      acBlkTblRec.AppendEntity(acHatch)

      acTrans.AddNewlyCreatedDBObject(acHatch, True)

      '' Set the properties of the hatch object

      '' Associative must be set after the hatch object is appended to the

      '' block table record and before AppendLoop

      acHatch.SetHatchPattern(HatchPatternType.PreDefined, "ANSI31")

      acHatch.Associative = True

      acHatch.AppendLoop(HatchLoopTypes.Outermost, acObjIdColl)

      acHatch.EvaluateHatch(True)

      '' Save the new object 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("AddHatch")]

public static void AddHatch()

  // Get the current document and database

  Document acDoc = Application.DocumentManager.MdiActiveDocument;

  Database acCurDb = acDoc.Database;

  // Start a transaction

  using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())

      // Open the Block table 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 circle object for the closed boundary to hatch

      Circle acCirc = new Circle();

      acCirc.Center = new Point3d(3, 3, 0);

      acCirc.Radius = 1;

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

      acBlkTblRec.AppendEntity(acCirc);

      acTrans.AddNewlyCreatedDBObject(acCirc, true);

      // Adds the circle to an object id array

      ObjectIdCollection acObjIdColl = new ObjectIdCollection();

      acObjIdColl.Add(acCirc.ObjectId);

      // Create the hatch object and append it to the block table record

      Hatch acHatch = new Hatch();

      acBlkTblRec.AppendEntity(acHatch);

      acTrans.AddNewlyCreatedDBObject(acHatch, true);

      // Set the properties of the hatch object

      // Associative must be set after the hatch object is appended to the

      // block table record and before AppendLoop

      acHatch.SetHatchPattern(HatchPatternType.PreDefined, "ANSI31");

      acHatch.Associative = true;

      acHatch.AppendLoop(HatchLoopTypes.Outermost, acObjIdColl);

      acHatch.EvaluateHatch(true);

      // Save the new object to the database

      acTrans.Commit();

VBA/ActiveX Code Reference