Create Ordinate Dimensions (.NET)

Ordinate, or datum, dimensions measure the perpendicular distance from an origin point, called the datum, to a dimensioned feature, such as a hole in a part. These dimensions prevent escalating errors by maintaining accurate offsets of the features from the datum.

Ordinate dimensions consist of an X or Y ordinate with a leader line. X-datum ordinate dimensions measure the distance of a feature from the datum along the X axis. Y-datum ordinate dimensions measure the same distance along the Y axis. AutoCAD uses the origin of the current user coordinate system (UCS) to determine the measured coordinates. The absolute value of the coordinate is used.

The dimension text is aligned with the ordinate leader line regardless of the orientation defined by the current dimension style. You can accept the default text or override it with your own.

You create an ordinate dimension by creating an instance of an OrdinateDimension object. When you create an instance of an OrdinateDimension object, its constructor can accept an optional set of parameters. The following parameters can be supplied when you create a new OrdinateDimension object:

When passing values into the OrdinateDimension object constructor, the first value is a boolean flag which specifies whether the dimension is an X-datum or Y-datum ordinate dimension. If you enter TRUE, an X-datum ordinate dimension is created. If you enter FALSE, a Y-datum ordinate dimension is created. The UsingXAxis property can also be used to specify if an ordinate dimension is an X-datum or Y-datum.

Create an ordinate dimension

This example creates an ordinate dimension in Model space.

VB.NET

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
 
<CommandMethod("CreateOrdinateDimension")> _
Public Sub CreateOrdinateDimension()
    '' 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 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 an ordinate dimension
        Using acOrdDim As OrdinateDimension = New OrdinateDimension()
            acOrdDim.UsingXAxis = True
            acOrdDim.DefiningPoint = New Point3d(5, 5, 0)
            acOrdDim.LeaderEndPoint = New Point3d(10, 5, 0)
            acOrdDim.DimensionStyle = acCurDb.Dimstyle

            '' Add the new object to Model space and the transaction
            acBlkTblRec.AppendEntity(acOrdDim)
            acTrans.AddNewlyCreatedDBObject(acOrdDim, True)
        End Using

        '' Commit the changes and dispose of the transaction
        acTrans.Commit()
    End Using
End Sub

C#

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
 
[CommandMethod("CreateOrdinateDimension")]
public static void CreateOrdinateDimension()
{
    // Get the current 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 an ordinate dimension
        using (OrdinateDimension acOrdDim = new OrdinateDimension())
        {
            acOrdDim.UsingXAxis = true;
            acOrdDim.DefiningPoint = new Point3d(5, 5, 0);
            acOrdDim.LeaderEndPoint = new Point3d(10, 5, 0);
            acOrdDim.DimensionStyle = acCurDb.Dimstyle;

            // Add the new object to Model space and the transaction
            acBlkTblRec.AppendEntity(acOrdDim);
            acTrans.AddNewlyCreatedDBObject(acOrdDim, true);
        }

        // Commit the changes and dispose of the transaction
        acTrans.Commit();
    }
}

VBA/ActiveX Code Reference

Sub CreateOrdinateDimension()
    Dim dimObj As AcadDimOrdinate
    Dim definingPoint(0 To 2) As Double
    Dim leaderEndPoint(0 To 2) As Double
    Dim useXAxis As Boolean
 
    ' Define the dimension
    definingPoint(0) = 5
    definingPoint(1) = 5
    definingPoint(2) = 0
    leaderEndPoint(0) = 10
    leaderEndPoint(1) = 5
    leaderEndPoint(2) = 0
    useXAxis = True
 
    ' Create an ordinate dimension in model space
    Set dimObj = ThisDrawing.ModelSpace. _
                     AddDimOrdinate(definingPoint, _
                     leaderEndPoint, useXAxis)
 
    ZoomAll
End Sub

Related Concepts