Modifying an existing sketch arc using VBA

[nick.seman]

I have the need to update an existing sketch arc via VBA.  I cannot delete and replace it as I have downstream dependencies.  I am almost able to accomplish it by constraining the start, center, and end points to sketch points (based on work points) and then programmatically modifying the locations of the work points - which works except when the curve direction of the arc (left or right) flips.

While I am able to harvest all the information about the existing arc using "SketchArc" I do not see any way to update the definition.

Can anyone provide any ideas or direction on this?

Thanks;

Nickl

[JelteDeJong]

The properties of an arc seem to be read-only so that means there is no way to change an arc. But you can create a new arc (using the properies of the old arc.) and then delete the old arc.

the fuction to create an arc has a optional (boolean) paramater to tell Inventor to draw the arc clock or counter clock wise. In the following example I draw 2 arcs. the first is clockwise and the other countercockwise. Notice the boolean at the end of line 6 and 7.

Dim otg = ThisApplication.TransientGeometry
Dim doc As PartDocument = ThisDoc.Document

Dim sketch As Sketch = doc.ComponentDefinition.Sketches.Add(doc.ComponentDefinition.WorkPlanes.Item(1))
sketch.Edit()
Dim arc1 = sketch.SketchArcs.AddByCenterStartEndPoint(otg.CreatePoint2d(0, 0), otg.CreatePoint2d(10, 0), otg.CreatePoint2d(0, 10), True)
Dim arc2 = sketch.SketchArcs.AddByCenterStartEndPoint(otg.CreatePoint2d(-1, -1), otg.CreatePoint2d(9, -1), otg.CreatePoint2d(-1, 9), False)

[nick.seman]

That is pretty much what I had arrived at as well.   Problem is that it breaks my downstream processes if I create a new arc and delete the exisitng.  I think I might be able to change my approach to manipulating the work points' locations that the existing arc follows.

Thanks for looking at it for me.

Nick

[bradeneuropeArthur]

Could you demonstrate with maybe pictures what you try to modify?

[JelteDeJong]

Moving the arc by manipulating the sketch points seems possible:

Dim otg = ThisApplication.TransientGeometry
Dim doc As PartDocument = ThisDoc.Document

Dim sketch As Sketch = doc.ComponentDefinition.Sketches.Add(doc.ComponentDefinition.WorkPlanes.Item(1))
sketch.Edit()
Dim arc1 = sketch.SketchArcs.AddByCenterStartEndPoint(otg.CreatePoint2d(0, 0), otg.CreatePoint2d(10, 0), otg.CreatePoint2d(0, 10), True)
Dim arc2 = sketch.SketchArcs.AddByCenterStartEndPoint(otg.CreatePoint2d(-1, -1), otg.CreatePoint2d(9, -1), otg.CreatePoint2d(-1, 9), False)

MsgBox("Now move.")
arc1.CenterSketchPoint.MoveTo(otg.CreatePoint2d(1, 1))
arc1.StartSketchPoint.MoveTo(otg.CreatePoint2d(11, 1))
arc1.EndSketchPoint.MoveTo(otg.CreatePoint2d(1, 11))