Use the Explode method to break a block reference.
By exploding a block reference, you can modify the block or add to or delete the objects that define it.
This example creates a block and adds a circle to the definition of the block. The block is then inserted into the drawing as a block reference. The block reference is then exploded, and the objects resulting from the explode process are displayed along with their object types.
Sub Ch10_ExplodingABlock() ' Define the block Dim blockObj As AcadBlock Dim insertionPnt(0 To 2) As Double insertionPnt(0) = 0 insertionPnt(1) = 0 insertionPnt(2) = 0 Set blockObj = ThisDrawing.Blocks.Add _ (insertionPnt, "CircleBlock") ' Add a circle to the block Dim circleObj As AcadCircle Dim center(0 To 2) As Double Dim radius As Double center(0) = 0 center(1) = 0 center(2) = 0 radius = 1 Set circleObj = blockObj.AddCircle(center, radius) ' Insert the block Dim blockRefObj As AcadBlockReference insertionPnt(0) = 2 insertionPnt(1) = 2 insertionPnt(2) = 0 Set blockRefObj = ThisDrawing.ModelSpace.InsertBlock _ (insertionPnt, "CircleBlock", 1#, 1#, 1#, 0) ZoomAll MsgBox "The circle belongs to " & blockRefObj.ObjectName ' Explode the block reference Dim explodedObjects As Variant explodedObjects = blockRefObj.Explode ' Loop through the exploded objects Dim I As Integer For I = 0 To UBound(explodedObjects) explodedObjects(I).Color = acRed explodedObjects(I).Update MsgBox "Exploded Object " & I & ": " _ & explodedObjects(I).ObjectName explodedObjects(I).Color = acByLayer explodedObjects(I).Update Next End Sub