Adjust Snap and Grid Alignment

The grid is a visual guideline to measure distances, while Snap mode is used to restrict cursor movement. In addition to setting the spacing for the grid and Snap mode, you can adjust the rotation and type of snap used.

If you need to draw along a specific alignment or angle, you can rotate the snap angle. The center point of the snap angle rotation is the snap base point.

NoteAfter changing the snap and grid settings for the active viewport, you should use the UpdateTiledViewportsFromDatabase method of the Editor object to update the display of the drawing area.

Snap and grid do not affect points specified through the .NET API, but do affect points specified in the drawing area by the user if they are requested to enter input using methods such as GetPoint or GetEntity. See “Adjust Grid and Grid Snap” in the AutoCAD User's Guide for more information on using and setting snaps and grids.

Change the grid and snap settings

This example changes the snap base point to (1,1) and the snap rotation angle to 30 degrees. The grid is turned on the spacing is adjusted so that the changes are visible.

VB.NET

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.Geometry

<CommandMethod("ChangeGridAndSnap")> _

Public Sub ChangeGridAndSnap()

  '' Get the current 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 active viewport

      Dim acVportTblRec As ViewportTableRecord

      acVportTblRec = acTrans.GetObject(acDoc.Editor.ActiveViewportId, _

                                        OpenMode.ForWrite)

      '' Turn on the grid for the active viewport

      acVportTblRec.GridEnabled = True

      '' Adjust the spacing of the grid to 1, 1

      acVportTblRec.GridIncrements = New Point2d(1, 1)

      '' Turn on the snap mode for the active viewport

      acVportTblRec.SnapEnabled = True

      '' Adjust the snap spacing to 0.5, 0.5

      acVportTblRec.SnapIncrements = New Point2d(0.5, 0.5)

      '' Change the snap base point to 1, 1

      acVportTblRec.SnapBase = New Point2d(1, 1)

      '' Change the snap rotation angle to 30 degrees (0.524 radians)

      acVportTblRec.SnapAngle = 0.524

      '' Update the display of the tiled viewport

      acDoc.Editor.UpdateTiledViewportsFromDatabase()

      '' Commit the changes and dispose of the transaction

      acTrans.Commit()

  End Using

End Sub

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.Geometry;

[CommandMethod("ChangeGridAndSnap")]

public static void ChangeGridAndSnap()

  // Get the current database

  Document acDoc = Application.DocumentManager.MdiActiveDocument;

  Database acCurDb = acDoc.Database;

  // Start a transaction

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

      // Open the active viewport

      ViewportTableRecord acVportTblRec;

      acVportTblRec = acTrans.GetObject(acDoc.Editor.ActiveViewportId,

                                        OpenMode.ForWrite) as ViewportTableRecord;

      // Turn on the grid for the active viewport

      acVportTblRec.GridEnabled = true;

      // Adjust the spacing of the grid to 1, 1

      acVportTblRec.GridIncrements = new Point2d(1, 1);

      // Turn on the snap mode for the active viewport

      acVportTblRec.SnapEnabled = true;

      // Adjust the snap spacing to 0.5, 0.5

      acVportTblRec.SnapIncrements = new Point2d(0.5, 0.5);

      // Change the snap base point to 1, 1

      acVportTblRec.SnapBase = new Point2d(1, 1);

      // Change the snap rotation angle to 30 degrees (0.524 radians)

      acVportTblRec.SnapAngle = 0.524;

      // Update the display of the tiled viewport

      acDoc.Editor.UpdateTiledViewportsFromDatabase();

      // Commit the changes and dispose of the transaction

      acTrans.Commit();

VBA/ActiveX Code Reference