Edit Hatch Patterns (.NET)

You can change the angle or spacing of an existing hatch pattern or replace it with a solid-fill, gradient fill, or one of the predefined patterns that AutoCAD offers. The Pattern option in the Boundary Hatch dialog box or Pattern gallery on the ribbon displays a list of these patterns. To reduce file size, the hatch is defined in the drawing as a single graphic object.

Use the following properties and methods to edit the hatch patterns:

GradientAngle

Specifies the gradient angle of the hatch.

GradientName

Returns the gradient name of the hatch.

GradientShift

Specifies the gradient shift of the hatch.

GradientType

Returns the gradient type of the hatch.

PatternAngle

Specifies the angle (in radians) of the hatch pattern.

PatternDouble

Specifies if the user-defined hatch is double-hatched.

PatternName

Returns the hatch pattern name of the hatch. (Use the SetHatchPattern method to set the hatch pattern name and type of the hatch.)

PatternScale

Specifies the hatch pattern scale.

PatternSpace

Specifies the user-defined hatch pattern spacing.

PatternType

Returns the hatch pattern type of the hatch. (Use the SetHatchPattern method to set the hatch pattern name and type of the hatch.)

SetGradient

Sets the gradient type and name for the hatch.

SetHatchPattern

Sets the pattern type and name for the hatch.

Change the pattern spacing of a hatch

This example creates a hatch. It then adds two to the current pattern spacing for the hatch.

C# Example

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
 
[CommandMethod("EditHatchPatternScale")]
public static void EditHatchPatternScale()
{
    // 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 boundary of the hatch
        using (Circle acCirc = new Circle())
        {
            acCirc.Center = new Point3d(5, 3, 0);
            acCirc.Radius = 3;

            acBlkTblRec.AppendEntity(acCirc);
            acTrans.AddNewlyCreatedDBObject(acCirc, true);

            // Adds the arc and line to an object id collection
            ObjectIdCollection acObjIdColl = new ObjectIdCollection();
            acObjIdColl.Add(acCirc.ObjectId);

            // Create the hatch object and append it to the block table record
            using (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);

                // Evaluate the hatch
                acHatch.EvaluateHatch(true);

                // Increase the pattern scale by 2 and re-evaluate the hatch
                acHatch.PatternScale = acHatch.PatternScale + 2;
                acHatch.SetHatchPattern(acHatch.PatternType, acHatch.PatternName);
                acHatch.EvaluateHatch(true);
            }
        }

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