Use any of the Block object methods and properties to redefine a block. When you redefine a block, all the references to that block in the drawing are immediately updated to reflect the new definition.
Redefinition affects previous and future insertions of a block. Constant attributes are lost and replaced by any new constant attributes. Variable attributes remain unchanged, even if the new block has no attributes.
Redefine the objects in a block definition
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 circle in the block definition is updated, and the block reference is updated automatically.
Sub Ch10_RedefiningABlock()
' 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
' Redefine the circle in the block,
' and update the block reference
circleObj.radius = 3
blockRefObj.Update
End Sub
